ATARA BIOTHERAPEUTICS INC (ATRA)

Institutional ownership reported to the SEC as of Q2 2026, across 31 quarters.

Institutions report 4,504,594 shares against 10,037,710 outstanding. Shares only - option lines are excluded, which is why this can be compared with the company at all. The count comes from the cover page of the company's own most recent report, so it is dated when that was filed rather than at quarter end.

Calls and puts are the parts of reported value carried in derivative lines rather than shares, and they point in opposite directions: a manager holding calls is positioned for the security, one holding puts against it - or hedging shares they already own, which is why index funds carry so many. Most sites add the two together and report one figure, which averages away the only interesting part.

Holders

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Five percent filings

Anyone crossing 5% of a company must say so within days - far sooner than the next quarterly holdings report. A 13D declares an intent to influence the company; a 13G is the passive version. See all activist filings →

What the insiders did

Open market purchases and sales reported on Form 4 in the last 180 days. Grants, option exercises and shares surrendered to cover tax are left out: they are compensation rather than a decision to buy or sell. Where a broker filled one order in tranches the lines are summed, because it was one decision.

Officers and directors

Ten percent owners and entities

Usually an institution that crossed a reporting threshold, or a company taking a strategic stake, rather than an individual with a view.

Quarter by quarter

Coverage begins with the quarter ending 2018-12-31. Earlier filings exist only as occasional late amendments, too sparse to describe a market, so they are not shown.