How many insider purchases were disclosed in December 2025?

619 open-market insider purchases of $50K or more were disclosed across 265 companies by 333 distinct insiders in SEC Form 4 filings during December 2025, totaling $9.7B.

What was the biggest insider buy in December 2025?

The largest open-market insider purchase disclosed in December 2025 was $7.5B by GENMAB A/S at Merus N.V. (MRUS), filed with the SEC on Form 4.

Biggest Insider Buys: December 2025

The largest open-market insider purchases disclosed in SEC Form 4 filings, ranked by dollar value.

In December 2025, 619 open-market insider purchases of $50K or more were disclosed across 265 companies in SEC Form 4 filings, totaling $9.7B. The largest single purchase was $7.5B by GENMAB A/S at Merus N.V. (MRUS).

← All monthly rankings

Largest purchases · December 2025

							Source
MRUS	GENMAB A/S	10% Owner	Purchase	76,920,005	$7.5B	Dec 30	SEC ↗
MDLN	GIC Private Ltd	10% Owner	Purchase	12,586,206	$365.0M	Dec 22	SEC ↗
IMVT	Roivant Sciences Ltd.	Director, 10% Owner	Purchase	16,666,666	$350.0M	Dec 12	SEC ↗
KYMR	BAKER BROS. ADVISORS LP	Director, 10% Owner	Purchase	2,005,813	$172.5M	Dec 11	SEC ↗
MDLN	Mills Andrew J.	Director	Purchase	2,586,206	$75.0M	Dec 22	SEC ↗
MDLN	Mills Charles N.	Director	Purchase	2,579,310	$74.8M	Dec 22	SEC ↗
KOD	BAKER BROS. ADVISORS LP	Director, 10% Owner	Purchase	2,608,696	$60.0M	Dec 19	SEC ↗
GDV.M	GABELLI MARIO J	Control Person of Adviser	Purchase	5,818,500	$58.2M	Dec 31	SEC ↗
KVUE	Smith Jeffrey C	Director	Purchase	3,200,000	$55.6M	Dec 15	SEC ↗
KVUE	Smith Jeffrey C	Director	Purchase	3,177,694	$55.4M	Dec 15	SEC ↗
MRUS	GENMAB A/S	10% Owner	Purchase	561,042	$54.4M	Dec 29	SEC ↗
MGM	IAC Inc.	10% Owner	Purchase	1,098,748	$39.9M	Dec 9	SEC ↗
MBAV	CANTOR FITZGERALD & CO.	10% Owner	Purchase	3,529,081	$38.1M	Dec 19	SEC ↗
UA	WATSA V PREM ET AL	10% Owner	Purchase	7,739,154	$34.6M	Dec 29	SEC ↗
WVE	GSK plc	10% Owner	Purchase	1,470,000	$27.9M	Dec 15	SEC ↗
CRM	Morfit G Mason	See Remarks	Purchase	96,000	$25.0M	Dec 8	SEC ↗
HYMC	Sprott Eric	10% Owner	Purchase	2,340,824	$24.1M	Dec 5	SEC ↗
MRUS	GENMAB A/S	10% Owner	Purchase	212,177	$20.6M	Dec 22	SEC ↗
CBIO	Fairmount Funds Management LLC	Director, 10% Owner	Purchase	1,360,000	$18.2M	Dec 8	SEC ↗
SEVN	PORTNOY ADAM D.	Director, 10% Owner	Purchase	2,015,748	$17.4M	Dec 11	SEC ↗
WRB	MITSUI SUMITOMO INSURANCE CO LTD	10% Owner	Purchase	234,573	$16.5M	Dec 29	SEC ↗
WRB	MITSUI SUMITOMO INSURANCE CO LTD	10% Owner	Purchase	220,000	$15.5M	Dec 29	SEC ↗
WRB	MITSUI SUMITOMO INSURANCE CO LTD	10% Owner	Purchase	220,000	$15.5M	Dec 29	SEC ↗
MRUS	GENMAB A/S	10% Owner	Purchase	150,795	$14.6M	Dec 18	SEC ↗
WRB	MITSUI SUMITOMO INSURANCE CO LTD	10% Owner	Purchase	205,000	$14.5M	Dec 29	SEC ↗

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