What changed in this filing

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Item 1. Financial Statements

2026-07-30 compared with 2026-05-06 · 203 added, 137 removed, 628 unchanged (35% of the section changed)

3 unchanged sentences

(in thousands, except share and per share data)

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

ASSETS (unaudited)

30 unchanged sentences

Preferred stock, $ 0.001 par value per share;

10,000,000 shares authorized as of March 31, 2026 and December 31, 2025;

no shares issued and outstanding as of March 31, 2026 and December 31, 2025

10,000,000 shares authorized as of June 30, 2026 and December 31, 2025;

no shares issued and outstanding as of June 30, 2026 and December 31, 2025

Common stock, $ 0.001 par value per share;

200,000,000 shares authorized as of March 31, 2026 and December 31, 2025;

30,295,965 and 29,686,314 shares issued and outstanding as of March 31, 2026 and December 31, 2025, respectively

200,000,000 shares authorized as of June 30, 2026 and December 31, 2025;

30,508,534 and 29,686,314 shares issued and outstanding as of June 30, 2026 and December 31, 2025, respectively

Additional paid-in capital 711,121 694,860

8 unchanged sentences

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

NET REVENUES $ 103,546 $ 86,188 $ 187,225 $ 174,176

7 unchanged sentences

Interest income 2,356 2,944 4,901 6,043

Net gains (losses) on equity securities 2,022 ( 1,425 )

Net (losses) gains on equity securities ( 630 ) 1,185 1,392 ( 240 )

Interest expense ( 193 ) ( 21 ) ( 327 ) ( 38 )

2 unchanged sentences

Income tax expense (benefit) 370 ( 4,666 ) 479 ( 5,089 )

Net loss $ ( 14,522 ) $ ( 25,848 )

Loss per share, basic and diluted

$ ( 0.49 ) $ ( 0.90 )

Weighted-average shares outstanding, basic and diluted

29,889 28,609

Net (loss) income $ ( 2,060 ) $ 4,523 $ ( 16,582 ) $ ( 21,325 )

(Loss) earnings per share:

Basic $ ( 0.07 ) $ 0.16 $ ( 0.55 ) $ ( 0.74 )

Diluted $ ( 0.07 ) $ 0.15 $ ( 0.55 ) $ ( 0.74 )

Weighted-average shares outstanding:

Basic 30,399 28,914 30,148 28,763

Diluted 30,399 29,545 30,148 28,763

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

CASTLE BIOSCIENCES, INC.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME

(in thousands)

Three Months Ended

Net loss $ ( 14,522 ) $ ( 25,848 )

June 30, Six Months Ended

2026 2025 2026 2025

Net (loss) income $ ( 2,060 ) $ 4,523 $ ( 16,582 ) $ ( 21,325 )

Other comprehensive loss:

Net unrealized loss on marketable investment securities ( 193 ) ( 92 ) ( 523 ) ( 191 )

Comprehensive loss $ ( 14,852 ) $ ( 25,947 )

Comprehensive (loss) income $ ( 2,253 ) $ 4,431 $ ( 17,105 ) $ ( 21,516 )

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

18 unchanged sentences

28,844,937 $ 29 $ 666,120 $ ( 225,974 ) $ 131 $ 440,306

Stock-based compensation expense — — 11,208 — — 11,208

Exercise of common stock options 10,664 — 19 — — 19

Issuance of common stock from vested restricted stock units, net of shares withheld for taxes 125,550 — ( 588 ) — — ( 588 )

Net unrealized loss on marketable investment securities — — — — ( 92 ) ( 92 )

Net income — — — 4,523 — 4,523

BALANCE, JUNE 30, 2025

28,981,151 $ 29 $ 676,759 $ ( 221,451 ) $ 39 $ 455,376

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

CASTLE BIOSCIENCES, INC.

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY

(in thousands, except share data)

Common Stock Additional

14 unchanged sentences

30,295,965 $ 30 $ 700,255 $ ( 238,806 ) $ ( 63 ) $ 461,416

Stock-based compensation expense — — 11,589 — — 11,589

Exercise of common stock options 32,990 — 95 — — 95

Issuance of common stock from vested restricted stock units, net of shares withheld for taxes 179,579 1 ( 818 ) — — ( 817 )

Net unrealized loss on marketable investment securities — — — — ( 193 ) ( 193 )

Net loss — — — ( 2,060 ) — ( 2,060 )

BALANCE, JUNE 30, 2026

30,508,534 $ 31 $ 711,121 $ ( 240,866 ) $ ( 256 ) $ 470,030

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

2 unchanged sentences

(in thousands)

Three Months Ended

Six Months Ended

OPERATING ACTIVITIES

6 unchanged sentences

Accretion of discounts on marketable investment securities ( 846 ) ( 2,606 )

Other 767 219

Change in operating assets and liabilities:

8 unchanged sentences

Other accrued and current liabilities 5,314 474

Net cash used in operating activities ( 22,129 ) ( 6,036 )

Net cash (used in) provided by operating activities ( 6,928 ) 14,785

INVESTING ACTIVITIES

1 unchanged sentence

Proceeds from maturities of marketable investment securities 80,100 80,300

Proceeds from maturities of debt securities classified as held-to-maturity 5,600 —

Purchases of debt securities classified as held-to-maturity — ( 5,569 )

Proceeds from sale of equity securities 3,248 —

Asset acquisition, net of cash and cash equivalents acquired — ( 18,726 )

Purchases of property and equipment ( 21,105 ) ( 14,003 )

5 unchanged sentences

Proceeds from contributions to the employee stock purchase plan 2,103 1,482

Payment of contingent consideration ( 1,000 ) —

Repayment of principal portion of finance lease liabilities ( 48 ) ( 57 )

Net cash used in financing activities ( 5,033 ) ( 1,553 )

NET CHANGE IN CASH AND CASH EQUIVALENTS ( 52,965 ) ( 30,020 )

Beginning of period 116,729 119,709

End of period $ 63,764 $ 89,689

The accompanying notes are an integral part of these unaudited condensed consolidated financial statements.

2 unchanged sentences

(in thousands)

Three Months Ended

Six Months Ended

Proceeds from lease incentives received — 190

Net cash used in financing activities ( 5,919 ) ( 1,452 )

NET CHANGE IN CASH AND CASH EQUIVALENTS ( 54,613 ) ( 37,476 )

Beginning of period 116,729 119,709

End of period $ 62,116 $ 82,233

Six Months Ended

DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:

Asset acquisition, liability for contingent consideration $ — $ 2,500

Accrued purchases of property and equipment $ 1,034 $ 6,822

Property and equipment acquired with tenant improvement allowance $ — $ 7,224

Operating lease assets obtained in exchange for lease obligations $ — $ 4,687

Decrease in operating lease assets with corresponding change in lease liabilities $ — $ ( 104 )

Finance lease assets obtained in exchange for lease obligations $ 4 $ 119

12 unchanged sentences

All intercompany accounts and transactions have been eliminated in consolidation.

We have a history of recurring net losses and negative cash flows and as of March 31, 2026, we had an accumulated deficit of $ 238.8 million.

We believe our $ 63.8 million of cash and cash equivalents and $ 197.9 million of marketable investment securities as of March 31, 2026, and anticipated revenue from our test reports, will be sufficient to meet our cash requirements through at least the 12-month period following the date that these unaudited condensed consolidated financial statements were issued.

We have a history of recurring net losses and negative cash flows and as of June 30, 2026, we had an accumulated deficit of $ 240.9 million.

We believe our $ 62.1 million of cash and cash equivalents and $ 204.7 million of marketable investment securities as of June 30, 2026, and anticipated revenue from our test reports, will be sufficient to meet our cash requirements through at least the 12-month period following the date that these unaudited condensed consolidated financial statements were issued.

Unaudited Interim Financial Information

The accompanying condensed consolidated balance sheet as of March 31, 2026;

the condensed consolidated statements of operations, the condensed consolidated statements of comprehensive loss and the condensed consolidated statements of stockholders’ equity, each for the three months ended March 31, 2026 and 2025;

and the condensed consolidated statements of cash flows for the three months ended March 31, 2026 and 2025 are unaudited.

The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of our consolidated financial position as of March 31, 2026, the results of our consolidated operations for the three months ended March 31, 2026 and 2025 and our consolidated cash flows for the three months ended March 31, 2026 and 2025.

The financial data and other information disclosed in these notes related to the three months ended March 31, 2026 and 2025 are also unaudited.

The results for the three months ended March 31, 2026 are not necessarily indicative of results to be expected for the year ending December 31, 2026, any other interim periods, or any future year or period.

The accompanying condensed consolidated balance sheet as of June 30, 2026;

the condensed consolidated statements of operations, the condensed consolidated statements of comprehensive (loss) income and the condensed consolidated statements of stockholders’ equity, each for the three and six months ended June 30, 2026 and 2025;

and the condensed consolidated statements of cash flows for the six months ended June 30, 2026 and 2025 are unaudited.

The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of our consolidated financial position as of June 30, 2026, the results of our consolidated operations for the three and six months ended June 30, 2026 and 2025 and our consolidated cash flows for the six months ended June 30, 2026 and 2025.

The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2026 and 2025 are also unaudited.

The results for the three and six months ended June 30, 2026 are not necessarily indicative of results to be expected for the year ending December 31, 2026, any other interim periods, or any future year or period.

The balance sheet as of December 31, 2025 included herein was derived from the audited financial statements as of that date.

1 unchanged sentence

These unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2025 filed with the Securities and Exchange Commission on February 26, 2026.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Use of Estimates

5 unchanged sentences

Actual results could differ from those estimates and assumptions.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Segment Reporting

Operating segments are components of an enterprise engaging in business activities from which it may recognize revenues and incur expenses, where discrete financial information is available, and where its operating results are regularly reviewed by the public entity’s chief operating decision maker (“CODM”) to make decisions about resources to be allocated to the segment and to assess its performance.

A CODM may be an individual or a decision-making group.

A reportable segment consists of one or more operating segments.

For additional information on our segment reporting, see Note 15.

Cash and Cash Equivalents including Concentrations of Credit Risk

31 unchanged sentences

These changes are allocated to the acquired assets based on their relative fair values as of the date of acquisition.

In December 2025 and March 2026, two commercial milestones were achieved, resulting in aggregate Earnout Payments of $ 1.0 million becoming payable.

The payment related to the initial milestone was extended.

Both earnout payments are expected to be made within 60 days following the end of the period.

Contingent consideration is classified as current or noncurrent in the condensed consolidated balance sheets based on the contractual timing of future settlement.

During the six months ended June 30, 2026, we made aggregate Earnout Payments of $ 1.0 million upon the achievement of certain commercial milestones.

Contingent consideration is classified as current in the condensed consolidated balance sheets based on the contractual timing of future settlement.

Revenue Recognition

13 unchanged sentences

Following approval under the Swedish Screening of Foreign Direct Investments Act in the third quarter of 2025, we completed our investment in SciBase.

The agreement aims to jointly develop diagnostic tests for dermatologic diseases, initially focused on atopic dermatitis, by combining SciBase’s Electrical Impedance Spectroscopy technology with our diagnostic and development expertise.

The agreement aims to jointly develop products for dermatologic diseases, initially focused on atopic dermatitis, by combining SciBase’s Electrical Impedance Spectroscopy technology with our diagnostic and development expertise.

Under the arrangement, we hold development and commercialization rights in North America, while SciBase retains rights in certain other territories.

15 unchanged sentences

Historically, our credit losses have not been significant.

The allowance for credit losses was zero as of March 31, 2026 and December 31, 2025.

The allowance for credit losses was zero as of June 30, 2026 and December 31, 2025.

Adjustments for implicit price concessions attributable to variable consideration, as discussed below, are incorporated into the measurement of the accounts receivable balances and are not part of the allowance for credit losses.

38 unchanged sentences

We also accrue for liabilities under employee sales incentive bonus plans with accruals based on performance achieved to date compared to established targets.

As of March 31, 2026 and December 31, 2025, we accrued approximately $ 7.9 million and $ 28.1 million, respectively, for liabilities associated with these bonus plans.

As of June 30, 2026 and December 31, 2025, we accrued approximately $ 17.4 million and $ 28.1 million, respectively, for liabilities associated with these bonus plans.

These amounts are classified as current accrued liabilities in the condensed consolidated balance sheets based on the expected timing of payment.

15 unchanged sentences

Forfeitures are accounted for as they occur.

Comprehensive Loss

Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources.

Comprehensive loss is made up of net loss plus net unrealized loss on marketable investment securities, which is our only other item of other comprehensive loss.

Comprehensive (Loss) Income

Comprehensive (loss) income is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources.

Comprehensive (loss) income is made up of net (loss) income plus net unrealized (loss) on marketable investment securities, which is our only other item of other comprehensive (loss) income.

CASTLE BIOSCIENCES, INC.

24 unchanged sentences

All of our revenues from contracts with customers are associated with the provision of testing services.

Our revenues are primarily attributable to our DecisionDx®-Melanoma test for cutaneous melanoma and our TissueCypher® test for patients diagnosed with Barrett’s esophagus.

Our revenues are primarily attributable to our TissueCypher® test for patients diagnosed with Barrett’s esophagus and our DecisionDx®-Melanoma test for cutaneous melanoma.

We also provide our DecisionDx®-UM test for uveal melanoma, MyPath® Melanoma test for patients with melanocytic lesions and our DecisionDx®-SCC test for cutaneous squamous cell carcinoma.

20 unchanged sentences

Variable consideration is evaluated each reporting period and adjustments are recorded as increases or decreases in revenues.

Included in revenues for the three months ended March 31, 2026 and 2025 were $ 0.6 million of net negative and $ 0.8 million of net positive revenue adjustments, respectively, associated with changes in estimated variable consideration related to performance obligations satisfied in previous periods.

Included in revenues for the three months ended June 30, 2026 and 2025 were $ 3.7 million and less than $ 0.1 million of net positive revenue adjustments, respectively, associated with changes in estimated variable consideration related to performance obligations satisfied in previous periods.

Included in revenues for the six months ended June 30, 2026 and 2025 were $ 1.3 million and $ 2.0 million of net negative revenue adjustments, respectively, associated with changes in estimated variable consideration related to performance obligations satisfied in previous periods.

These amounts include (i) adjustments for actual collections versus estimated amounts and (ii) cash collections and the related recognition of revenue in current period for tests delivered in prior periods due to the release of the constraint on variable consideration.

1 unchanged sentence

Any incremental costs to obtain contracts are recorded as selling, general and administrative expenses as incurred due to the short duration of our contracts.

Contract balances consisted solely of accounts receivable (both current and noncurrent) as of March 31, 2026 and December 31, 2025.

Contract balances consisted solely of accounts receivable (both current and noncurrent) as of June 30, 2026 and December 31, 2025.

Disaggregation of Revenues

1 unchanged sentence

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Dermatologic (1)

9 unchanged sentences

The characteristics for each test in our single segment are similar, with each test having a single performance obligation.

Our CODM is the single individual responsible for managing our segment and reviews consolidated results and budgets in assessing performance and in allocating resources.

Our chief operating decision maker (“CODM”) is the single individual responsible for managing our segment and reviews consolidated results and budgets in assessing performance and in allocating resources.

See Note 15 for additional information about our reportable segment.

8 unchanged sentences

(noncurrent) as of

Three Months Ended

2026 2025 March 31, 2026 December 31, 2025 March 31, 2026 December 31, 2025

Six Months Ended

2026 2025 June 30, 2026 December 31, 2025 June 30, 2026 December 31, 2025

Medicare 40 % 47 % 20 % 18 % * *

2 unchanged sentences

* Less than 10%

Loss Per Share

Basic loss per share is computed by dividing net loss for the period by the weighted-average number of common shares outstanding during the period.

Diluted loss per share reflects the additional dilution from potential issuances of common stock, such as stock issuable pursuant to the exercise of stock options, vesting of RSUs and PSUs or purchases under the ESPP.

(Loss) Earnings Per Share

Basic (loss) earnings per share is computed by dividing net (loss) earnings for the period by the weighted-average number of common shares outstanding during the period.

Diluted (loss) earnings per share reflects the additional dilution from potential issuances of common stock, such as stock issuable pursuant to the exercise of stock options, vesting of RSUs and PSUs or purchases under the ESPP.

The treasury stock method is used to calculate the potential dilutive effect of these common stock equivalents.

Contingently issuable PSU awards are included in the computation of diluted loss per share when the applicable performance criteria would be met and the common shares would be issuable if the end of the reporting period were the end of the contingency period.

However, potentially dilutive shares are excluded from the computation of diluted loss per share when their effect is antidilutive.

Because we reported a net loss for all periods presented, all potentially dilutive securities are antidilutive and are excluded from the computation of diluted loss per share for such periods.

The table below provides the weighted-average number of potential common shares associated with outstanding securities not included in our calculation of diluted loss per share for the three months ended March 31, 2026 and 2025 because to do so would be antidilutive or, in the case of PSUs, the applicable performance conditions have not yet been met (in thousands):

Contingently issuable PSU awards are included in the computation of diluted (loss) earnings per share when the applicable performance criteria would be met and the common shares would be issuable if the end of the reporting period were the end of the contingency period.

However, potentially dilutive shares are excluded from the computation of diluted (loss) earnings per share when their effect is antidilutive.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

The following table shows the computation of basic and diluted earnings (loss) per share (in thousands, except per share data):

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Net (loss) income $ ( 2,060 ) $ 4,523 $ ( 16,582 ) $ ( 21,325 )

Weighted-average common shares outstanding, basic 30,399 28,914 30,148 28,763

Assumed exercise of stock options — 361 — —

Assumed vesting of RSUs — 186 — —

Assumed vesting of PSUs — 84 — —

Assumed issuance of shares under the ESPP — — — —

Weighted-average common shares outstanding, diluted 30,399 29,545 30,148 28,763

(Loss) earnings per share:

Basic $ ( 0.07 ) $ 0.16 $ ( 0.55 ) $ ( 0.74 )

Diluted $ ( 0.07 ) $ 0.15 $ ( 0.55 ) $ ( 0.74 )

Due to the Company reporting a net loss for the three and six months ended June 30, 2026 and the six months ended June 30, 2025, all potentially dilutive securities are antidilutive and are excluded from the computations of diluted loss per share.

The table below provides the weighted-average number of potential common shares associated with outstanding securities not included in our calculation of diluted (loss) earnings per share for the three and six months ended June 30, 2026 and 2025 because to do so would be antidilutive.

In regard to the PSUs, we assume that the associated performance targets will be met at the target level of performance for purposes of calculating diluted earnings per share until such time that it is probable that actual performance will be above or below target (in thousands):

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Stock options 2,704 2,466 2,736 2,965

RSUs and PSUs 4,428 2,958 4,188 4,053

ESPP 244 123 250 150

Total 7,376 5,547 7,174 7,168

3 unchanged sentences

Marketable investment securities consisted of the following (in thousands):

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

Current marketable investment securities:

4 unchanged sentences

On January 26, 2026, in connection with SciBase’s rights offering, we completed an amendment to our previously disclosed subscription commitment.

We agreed to increase our commitment to subscribe for shares without subscription rights from 115.0 million shares to 125.0 million shares.

We increased our commitment to subscribe for shares without subscription rights from 115.0 million shares to 125.0 million shares.

This amendment was intended to achieve an outcome substantially similar to full participation under our subscription rights.

1 unchanged sentence

These purchased rights, together with our shares without subscription rights, aggregated to a total share purchase of 155.5 million shares for $ 3.6 million.

On June 4, 2026, SciBase announced a 1-for-100 reverse share split.

Following the reverse share split, our total share purchase now represents 1.55 million shares.

During the six months ended June 30, 2026, all of our HTM investments matured.

Equity Securities

1 unchanged sentence

Three Months Ended

Net gains (losses) on equity securities $ 2,022 $ ( 1,425 )

June 30, Six Months Ended

2026 2025 2026 2025

Net (losses) gains on equity securities $ ( 630 ) $ 1,185 $ 1,392 $ ( 240 )

Net (loss) recognized on equity securities sold ( 386 ) — ( 513 ) —

Net unrealized gains (losses) recognized on equity securities still held $ 2,149 $ ( 1,425 )

Net unrealized (losses) gains recognized on equity securities still held $ ( 244 ) $ 1,185 $ 1,905 $ ( 240 )

CASTLE BIOSCIENCES, INC.

2 unchanged sentences

The following tables present our debt securities (in thousands):

March 31, 2026

June 30, 2026

Amortized Cost Unrealized Estimated Fair Value

government securities - AFS $ 198,131 $ 7 $ ( 263 ) $ 197,875

government securities - HTM 5,597 2 — 5,599

Total debt securities $ 198,131 $ 7 $ ( 263 ) $ 197,875

5 unchanged sentences

Total debt securities $ 176,954 $ 280 $ ( 2 ) $ 177,232

government securities includes both AFS and HTM securities.

The AFS securities are available to be sold to meet operating needs or otherwise, but are generally held through maturity.

Our AFS securities are available to be sold to meet operating needs or otherwise, but are generally held through maturity.

We classify all AFS investments as current assets, as these are readily available for use in current operations.

As of March 31, 2026 and December 31, 2025, all of our AFS securities had contractual maturities of one year or less.

We classify our HTM investments as current assets, as we have the positive intent and ability to hold these investments to maturity, and all such maturities are less than one year from the balance sheet date.

As of June 30, 2026 and December 31, 2025, all of our AFS securities had contractual maturities of one year or less.

As of December 31, 2025, we classified our HTM investments as current assets, as we had the positive intent and ability to hold these investments to maturity, and all such maturities are less than one year from the balance sheet date.

We evaluated our U.S.

government securities under the AFS and HTM impairment model guidance, respectively, and determined our investment portfolio is comprised of low-risk, investment grade securities.

For the three months ended March 31, 2026 and 2025, unrealized losses on our AFS and HTM U.S.

government securities under the AFS impairment model guidance and determined our investment portfolio is comprised of low-risk, investment grade securities.

For the three and six months ended June 30, 2026 and 2025, unrealized losses on our AFS U.S.

government securities are not attributed to credit risk.

We believe that an allowance for credit losses is unnecessary because the unrealized losses on certain of our marketable investment securities are due to market factors.

The allowance for credit losses was zero as of March 31, 2026 and December 31, 2025.

There were no realized gains or losses on sales of debt securities for the three months ended March 31, 2026 and 2025.

In addition, no credit-related or noncredit-related impairment losses were recorded for the three months ended March 31, 2026 and 2025.

Accrued interest receivable for our AFS and HTM U.S.

The allowance for credit losses was zero as of June 30, 2026 and December 31, 2025.

There were no realized gains or losses on sales of AFS debt securities for the three and six months ended June 30, 2026 and 2025.

In addition, no credit-related or noncredit-related impairment losses were recorded for the three and six months ended June 30, 2026 and 2025.

Accrued interest receivable for our AFS U.S.

government securities is included in prepaid expenses and other current assets in the condensed consolidated balance sheets.

As of March 31, 2026 and December 31, 2025, the accrued interest receivable related to AFS securities was $ 1.3 million and $ 1.1 million, respectively.

As of March 31, 2026 and December 31, 2025, the accrued interest receivable related to HTM securities was immaterial.

As of June 30, 2026 and December 31, 2025, the accrued interest receivable related to AFS securities was $ 1.4 million and $ 1.1 million, respectively.

Accrued interest receivable related to HTM securities was immaterial as of December 31, 2025.

Additional information relating to the fair value of marketable investment securities can be found in Note 11.

3 unchanged sentences

Property and equipment, net consisted of the following (in thousands):

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

Land $ 7,245 $ 7,245

9 unchanged sentences

Upon completion, we commenced depreciation of the capitalized construction costs of the building over an estimated useful life of 39 years.

As of March 31, 2026, construction-in-progress related primarily to leasehold improvements for our office and laboratory facilities in Scottsdale, Arizona.

As of June 30, 2026, construction-in-progress related primarily to leasehold improvements for our office and laboratory facilities in Scottsdale, Arizona.

Depreciation expense was recorded in the condensed consolidated statements of operations as follows (in thousands):

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Cost of sales (exclusive of amortization of acquired intangible assets) $ 1,151 $ 909 $ 2,309 $ 1,812

3 unchanged sentences

Goodwill and Other Intangible Assets, Net

We had a single reportable segment consisting of a single operating segment where the operating segment and the single reporting unit were the same as of March 31, 2026 and December 31, 2025, where all goodwill was allocated.

As of March 31, 2026 and December 31, 2025, our goodwill was $ 10.7 million.

There were no accumulated impairments of goodwill as of March 31, 2026 or December 31, 2025.

We had a single reportable segment consisting of a single operating segment where the operating segment and the single reporting unit were the same as of June 30, 2026 and December 31, 2025, where all goodwill was allocated.

As of June 30, 2026 and December 31, 2025, our goodwill was $ 10.7 million.

There were no accumulated impairments of goodwill as of June 30, 2026 or December 31, 2025.

See Note 15 for additional information on our reportable segment.

3 unchanged sentences

Our other intangible assets, net consisted of the following (in thousands):

March 31, 2026

June 30, 2026

Gross carrying value Accumulated amortization Net Weighted-Average Remaining Life (in years)

7 unchanged sentences

Total other intangible assets, net $ 154,063 $ ( 65,181 ) $ 88,882

During the first quarter of 2025, we made the decision to discontinue our IDgenetix test offering, effective May 2025.

As a result of this decision, we further revised the estimated useful life of the asset and determined that the intangible asset should be fully amortized as of March 31, 2025.

This change resulted in an acceleration of amortization expense of approximately $ 20.1 million.

Amortization expense of intangible assets was $ 2.2 million and $ 28.3 million for the three months ended March 31, 2026 and 2025, respectively.

Amortization expense of intangible assets was $ 2.3 million and $ 4.5 million for the three and six months ended June 30, 2026, respectively, and $ 2.0 million and $ 30.3 million for the three and six months ended June 30, 2025, respectively.

Other Accrued and Current Liabilities

Other accrued and current liabilities consisted of the following (in thousands):

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

Accrued service fees $ 3,950 $ 3,213

Clinical studies 2,718 2,674

Self-insurance liability 4,593 —

Clinical studies 2,437 2,674

ESPP contributions 1,133 924

1 unchanged sentence

Total $ 14,114 $ 8,937

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Long-Term Debt

Our long-term debt is presented in the table below (in thousands):

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

Term debt $ 10,200 $ 10,200

3 unchanged sentences

Total long-term debt $ 7,158 $ 9,640

Future maturities of principal amounts on long-term debt as of March 31, 2026 were as follows (in thousands):

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Future maturities of principal amounts on long-term debt as of June 30, 2026 were as follows (in thousands):

Years Ending December 31,

9 unchanged sentences

Should we seek to further amend the terms of the 2024 LSA, the consent of the Lender would be required.

As of March 31, 2026, we were in compliance with all of the covenants.

As of June 30, 2026, we were in compliance with all of the covenants.

The 2024 LSA bears interest at a floating rate equal to the greater of (a) the WSJ Prime Rate plus 0.25 % or (b) 6.00 % per annum.

6 unchanged sentences

A discount on debt equal to this obligation was recorded on the draw date and is being amortized as additional interest expense using the effective interest method over the term of the debt.

As of March 31, 2026, no payment on principal has been made and the weighted-average effective interest rate for all outstanding debt under the 2024 Term Loan was 7.69 %.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

As of June 30, 2026, no payment on principal has been made and the weighted-average effective interest rate for all outstanding debt under the 2024 Term Loan was 7.69 %.

Interest Expense on Long-Term Debt

1 unchanged sentence

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Interest expense on long term debt $ 185 $ 203 $ 369 $ 405

1 unchanged sentence

Total $ 185 $ 9 $ 311 $ 17

Capitalized interest on construction-in-progress was not material following the substantial completion of our new headquarters in Friendswood, Texas as remaining construction-in-progress balances are not associated with outstanding borrowings.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Unit 1 Pittsburgh Lease

2 unchanged sentences

The lease includes tenant improvement allowances and provides for an extension option and a one -time early termination option, each subject to certain conditions.

As of March 31, 2026, the Unit 1 Pittsburgh Lease has not commenced, and accordingly, we have not recognized a right-of-use asset or lease liability in our condensed consolidated balance sheet.

As of June 30, 2026, the lessor had not made the underlying asset available for use, and accordingly, we have not recognized a right-of-use asset or lease liability in our condensed consolidated balance sheet.

Fair Value Measurements

11 unchanged sentences

Accordingly, the fair value estimates disclosed, or amounts recorded, may not be indicative of the amount that we or holders of the instruments could realize in a current market exchange.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

The tables below provide information, by level within the fair value hierarchy, of our financial assets and liabilities that are accounted for at fair value on a recurring basis as of March 31, 2026 and December 31, 2025 (in thousands):

As of March 31, 2026

The tables below provide information, by level within the fair value hierarchy, of our financial assets and liabilities that are accounted for at fair value on a recurring basis as of June 30, 2026 and December 31, 2025 (in thousands):

As of June 30, 2026

Quoted Prices in Active Markets for Identical Items (Level 1) Significant Other Observable Inputs

9 unchanged sentences

$ — $ 10,075 $ — $ 10,075

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

As of December 31, 2025

14 unchanged sentences

(4) Borrowings approximate their fair value as the interest rate is variable and reflects market rates.

government securities that are HTM investments and are carried at amortized costs.

The fair value of our HTM investments is classified as Level 1 of the fair value hierarchy.

As of December 31, 2025 we held U.S.

government securities that were classified as HTM investments and carried at amortized costs.

The fair value of our HTM investments was classified as Level 1 of the fair value hierarchy.

For additional information on the carrying amount and fair value of our HTM investments, see Note 5.

3 unchanged sentences

For additional information on the carrying amount and estimated fair value of our Convertible Loan Receivable, see Note 2.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Commitments and Contingencies

From time to time, we may be involved in legal proceedings arising in the ordinary course of business.

On February 1, 2024, we received a subpoena from the Department of Health and Human Services, Office of Inspector General, seeking documents and information concerning claims submitted for payment under federal healthcare programs.

On February 1, 2024, we received a subpoena from the U.S.

Department of Health and Human Services, Office of Inspector General, seeking documents and information concerning claims submitted for payment under federal healthcare programs.

The subpoena requested that we produce documents relating primarily to interactions with medical providers and billing to government-funded healthcare programs for our tests.

11 unchanged sentences

Under this provision, effective January 1, 2026, an additional 1,484,315 shares became available under the 2019 Plan.

As of March 31, 2026, 1,590,533 shares remained available for grant under the 2019 Plan.

As of June 30, 2026, 1,443,825 shares remained available for grant under the 2019 Plan.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Inducement Plan

1 unchanged sentence

The Inducement Plan provides for the granting of awards as inducement material to the grantee’s entering into employment with us to the extent such grantee was not previously an employee of ours or is entering into employment following a bona fide period of non-employment with us.

As of March 31, 2026, there were 746,182 shares available for grant under the amended Inducement Plan.

As of June 30, 2026, there were 574,512 shares available for grant under the amended Inducement Plan.

Stock Options

Stock option activity under our stock plans for the three months ended March 31, 2026 is set forth below:

Stock option activity under our stock plans for the six months ended June 30, 2026 is set forth below:

Weighted-Average

8 unchanged sentences

Forfeited/Cancelled ( 38,245 ) $ 46.61

Balance as of March 31, 2026 2,743,348 $ 36.71 4.3 $ 9,262

Exercisable as of March 31, 2026

Balance as of June 30, 2026 2,684,703 $ 37.06 4.1 $ 8,172

Exercisable as of June 30, 2026

2,684,037 $ 37.07 4.1 $ 8,172

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Restricted Stock Units

The following table summarizes our RSU activity for the three months ended March 31, 2026:

The following table summarizes our RSU activity for the six months ended June 30, 2026:

Restricted Stock Units Outstanding Weighted-Average Grant Date Fair Value

4 unchanged sentences

Forfeited/Cancelled ( 126,917 ) $ 24.30

Balance as of March 31, 2026

Balance as of June 30, 2026

4,147,773 $ 23.95

(1) The aggregate number of shares withheld upon vesting for employee tax obligations was 201,867 for the three months ended March 31, 2026.

(1) The aggregate number of shares withheld upon vesting for employee tax obligations was 240,690 for the six months ended June 30, 2026.

Performance-Based Restricted Stock Units

The following table summarizes our PSU activity for the three months ended March 31, 2026:

The following table summarizes our PSU activity for the six months ended June 30, 2026:

Performance-Based Restricted Stock Units Outstanding Weighted-Average Grant Date Fair Value

4 unchanged sentences

Forfeited/Cancelled — $ —

Balance as of March 31, 2026

Balance as of June 30, 2026

433,784 $ 24.15

(1) The aggregate number of shares withheld upon vesting for employee tax obligations was 28,797 for the three months ended March 31, 2026.

(1) The aggregate number of shares withheld upon vesting for employee tax obligations was 28,797 for the six months ended June 30, 2026.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Employee Stock Purchase Plan

The ESPP provides for certain automatic increases in the number of shares of common stock reserved for issuance, which resulted in an additional 296,863 shares becoming available under the ESPP effective January 1, 2026.

During the three months ended March 31, 2026, we issued 94,420 shares of common stock pursuant to scheduled purchases under the ESPP.

As of March 31, 2026, 1,373,056 shares remained available for issuance under the ESPP.

During the six months ended June 30, 2026, we issued 94,420 shares of common stock pursuant to scheduled purchases under the ESPP.

As of June 30, 2026, 1,373,056 shares remained available for issuance under the ESPP.

Determining Fair Value - Summary of Assumptions

The following table sets forth assumptions used to determine the fair value of the purchase rights issued under the ESPP:

Three Months Ended

Six Months Ended

Average expected term (years) 1.2 1.2

6 unchanged sentences

We use the closing price of our common stock on the date of grant to determine the fair value of RSUs and PSUs.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

There were no stock options granted for the three months ended March 31, 2026 and 2025.

For the three months ended March 31, 2026 and 2025, the weighted-average grant date fair value of the purchase rights granted under the ESPP was $ 11.27 and $ 9.43 per share, respectively.

There were no stock options granted for the six months ended June 30, 2026 and 2025.

For the six months ended June 30, 2026 and 2025, the weighted-average grant date fair value of the purchase rights granted under the ESPP was $ 11.27 and $ 9.43 per share, respectively.

Stock-Based Compensation Expense

1 unchanged sentence

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Cost of sales (exclusive of amortization of acquired intangible assets) $ 1,420 $ 1,422 $ 2,677 $ 2,878

2 unchanged sentences

Total stock-based compensation expense $ 11,589 $ 11,208 $ 21,365 $ 22,387

Included in total stock-based compensation expense is $ 0.2 million and $ 0.3 million for the three months ended March 31, 2026 and 2025, respectively, from the accelerated recognition of expense for modifications of awards falling in scope of the Retirement Policy.

As of March 31, 2026, the total unrecognized stock-based compensation cost related to outstanding awards was $ 94.5 million, which is expected to be recognized over a weighted-average period of 2.8 years.

Included in total stock-based compensation expense is $ 0.8 million and $ 0.2 million for the three months ended June 30, 2026 and 2025, respectively, and $ 1.0 million and $ 0.5 million for the six months ended June 30, 2026 and 2025, respectively, from the accelerated recognition of expense for modifications of awards falling in scope of the Retirement Policy.

As of June 30, 2026, the total unrecognized stock-based compensation cost related to outstanding awards was $ 90.4 million, which is expected to be recognized over a weighted-average period of 2.7 years.

The total unrecognized compensation cost will be adjusted for forfeitures in future periods as they occur.

Our effective tax rate was immaterial for the three months ended March 31, 2026 and 2025.

The effective rate for the three months ended March 31, 2026 and 2025 differed from our federal statutory rate of 21% primarily due to the tax impact from the valuation allowance for current year activity, state income taxes and the non-deductibility of other permanent items.

Our effective tax rate was ( 21.9 )% and ( 3.0 )% for the three and six months ended June 30, 2026.

The effective rate for the three and six months ended June 30, 2026 differed from our federal statutory rate of 21% primarily due to the tax impact from the valuation allowance for current year activity, state income taxes and the non-deductibility of other permanent items.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

During the three and six months ended June 30, 2025, we recognized income tax benefit of $ 4.7 million and $ 5.1 million, respectively, primarily from the reduction of the valuation allowance on deferred tax assets, recorded as a discrete benefit in the quarter ended June 30, 2025.

This release was primarily driven by the acquisition of Previse, which resulted in deferred tax liabilities related to acquired intangible assets.

The effective rate for the three and six months ended June 30, 2025 differed from our federal statutory rate of 21% primarily due to the tax impact from the valuation allowance for the period activity including the acquisition of Previse, state income taxes and the non-deductibility of other permanent items.

Segment and Related Information

3 unchanged sentences

We have a single reportable segment consisting of a single operating segment.

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

The measures of segment profit or loss for our single reportable segment were as follows (in thousands):

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Net revenues from external customers (1)

7 unchanged sentences

Other segment items 16,006 5,948 28,260 42,963

Segment loss $ ( 14,522 ) $ ( 25,848 )

Segment (loss) income $ ( 2,060 ) $ 4,523 $ ( 16,582 ) $ ( 21,325 )

(1) For information on disaggregation of segment revenue by type and information about payor concentration, see Note 3.

4 unchanged sentences

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

Interest income $ 2,356 $ 2,944 $ 4,901 $ 6,043

3 unchanged sentences

Stock-based compensation expense 11,589 11,208 21,365 22,387

Net gains (losses) on equity securities 2,022 ( 1,425 )

Net (losses) gains on equity securities ( 630 ) 1,185 1,392 ( 240 )

CASTLE BIOSCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Total assets for our reportable segment were located in the U.S.

and were $ 547.8 million and $ 578.6 million as of March 31, 2026 and December 31, 2025, respectively.

Expenditures for additions to long-lived assets were $ 5.2 million and $ 5.7 million for the three months ended March 31, 2026, and 2025, respectively.

and were $ 561.2 million and $ 578.6 million as of June 30, 2026 and December 31, 2025, respectively.

Expenditures for additions to long-lived assets were $ 5.6 million and $ 12.9 million for the three months ended June 30, 2026 and 2025, respectively, and $ 10.8 million and $ 18.6 million for the six months ended June 30, 2026, and 2025, respectively.

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-Q

Item 1. Financial Statements