RELATED PARTY TRANSACTIONS

3 Months Ended

Mar. 31, 2026

Related Party Transactions [Abstract]

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS

The Company was a subsidiary of Illumina, Inc. between August 19, 2021 to June 23, 2024. Subsequent to the Spin-Off, Illumina retained a 14.5% stake in the Company and was considered a related party. During the fourth quarter of 2025, Illumina reduced its ownership to less than 10%. As a result, Illumina is no longer considered a related party of the Company.

Illumina was both a customer and a major supplier of the Company’s reagents and capital equipment during the relevant periods. Goods and services transactions with Illumina are invoiced and paid when due.

Goods and services transactions with Illumina for the period during which Illumina qualified as a related party of the Company were as follows:

	Three Months Ended
(in thousands)	March 31, 2025
Screening revenue	$	77
Cost of screening revenue	1,511
Cost of development services revenue	163
Operating expenses—Research and development	1,396

In June 2024, the Company entered into an amendment to its Supply and Commercialization Agreement with Illumina (the “Illumina Supply Agreement”). Under the terms of the Illumina Supply Agreement, regardless of whether our products incorporate any Illumina technology, we will be obligated to pay Illumina a 9% royalty, subject to certain reductions and floors, in perpetuity on net sales generated by our products or revenues otherwise generated or received by us, subject to certain exceptions, in the field of oncology. The royalty is subject to anti-stacking provisions that allow royalty payments we make to other third parties to be deducted from the 9% royalty rate, to a floor of 7%. We expect that the royalty payments we will make to Illumina in the foreseeable future will result in a 7% royalty rate. After we have cumulatively paid Illumina royalties totaling $1 billion, the royalty rate will be reduced to 5%, without further adjustment.

Pursuant to the fourth amendment to the Illumina Supply Agreement, the perpetual royalty payment obligation to Illumina is suspended until December 24, 2026 or any earlier change of control of GRAIL, at which time royalty payments to Illumina will resume, without retroactive effect. Any royalty payments that we would have made under the Illumina Supply Agreement during the suspension period are deemed to have been paid for purposes of the cumulative $1 billion in royalty payments required to reduce the royalty rate to 5%.