ATTO

ATTO$23.89-0.63 (-2.57%)

Prev Close$24.52·MCap—·P/E—·Vol161.3K·Yield—

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Buys (12M)

$52.37M

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Sells (12M)

$4.48M

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Net Activity

Net Buyer

$47.89M

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Active Insiders

last 12 mo

Over the past 12 months, insider activity at ATTO (ATTO) has been dominated by buying, with 6 insider purchases totaling $52.37M and 2 insider sales totaling $4.48M. The most recent insider transaction was by GOLDMAN SACHS GROUP INC (other: Former 10% Owner), who sold $2.24M worth of shares on Aug 13, 2026.

ATTO Insider Trading Activity

Date	Insider	Role	Type	Shares	Avg Price	Value	Shares After
Aug 13, 2026	GOLDMAN SACHS GROUP INC	other: Former 10% Owner	Sell	105,307	$21.28	$2.24M0.7% OS	84,012-56%
Aug 13, 2026	WALSH COLIN	director	Buy	585,000	$17.58	$10.29M4.0% OS	3,020,632
Aug 13, 2026	GOLDMAN SACHS GROUP INC	other: Former 10% Owner	Buy	585,000	$17.58	$10.29M4.0% OS	3,020,632
Aug 13, 2026	WALSH COLIN	director	Sell	105,307	$21.28	$2.24M0.7% OS	84,012-56%
Aug 10, 2026	venBio Global Strategic Fund IV, L.P.	10 percent owner	Buy	382,352	$17.00	$6.50M2.6% OS	4,181,367
Aug 7, 2026	Sanofi	10 percent owner	Buy	300,000	$17.00	$5.10M2.1% OS	1,082,855+38%
Aug 7, 2026	Redmile Group, LLC	10 percent owner	Buy	600,000	$17.00	$10.20M4.1% OS	1,182,854+103%
Aug 6, 2026	Frazier Life Sciences XI, L.P.	10 percent owner	Buy	588,235	$17.00	$10.00M4.1% OS	6,154,213

ATTO Insider Buying Activity

The following table shows recent insider purchases of ATTO (ATTO) stock reported via SEC Form 4 filings.

Date	Insider	Role	Type	Shares	Avg Price	Value	Shares After
Aug 13, 2026	WALSH COLIN	director	Buy	585,000	$17.58	$10.29M4.0% OS	3,020,632
Aug 13, 2026	GOLDMAN SACHS GROUP INC	other: Former 10% Owner	Buy	585,000	$17.58	$10.29M4.0% OS	3,020,632
Aug 10, 2026	venBio Global Strategic Fund IV, L.P.	10 percent owner	Buy	382,352	$17.00	$6.50M2.6% OS	4,181,367
Aug 7, 2026	Sanofi	10 percent owner	Buy	300,000	$17.00	$5.10M2.1% OS	1,082,855+38%
Aug 7, 2026	Redmile Group, LLC	10 percent owner	Buy	600,000	$17.00	$10.20M4.1% OS	1,182,854+103%
Aug 6, 2026	Frazier Life Sciences XI, L.P.	10 percent owner	Buy	588,235	$17.00	$10.00M4.1% OS	6,154,213

ATTO Insider Selling Activity

The following table shows recent insider sales of ATTO (ATTO) stock reported via SEC Form 4 filings.

Date	Insider	Role	Type	Shares	Avg Price	Value	Shares After
Aug 13, 2026	GOLDMAN SACHS GROUP INC	other: Former 10% Owner	Sell	105,307	$21.28	$2.24M0.7% OS	84,012-56%
Aug 13, 2026	WALSH COLIN	director	Sell	105,307	$21.28	$2.24M0.7% OS	84,012-56%