EcoR1 Capital, LLC, 10% Owner at Atara Biotherapeutics, Inc. (ATRA), bought 507,407 shares at $9.35 ($4.7M) on 2026-05-07, disclosed to the SEC on 2026-05-11.
EcoR1 Capital, a 10% holder, purchased 507,407 shares at $9.35 on May 7, 2026, marking the largest insider purchase in the company's history. This move signals confidence in the recent FDA news regarding the regulatory pathway for tab-cel.
The stock has rallied significantly, gaining 78.48% over the past five days and 87.38% over the last month to reach $8.835, though it remains 53.85% below its 52-week high of $19.145.
Watch for the FDA to outline a regulatory pathway for tab-cel, as reported by Zacks on May 21, and the resubmission path discussed by InvestorsHub on May 7.
The stock carries risk due to a short interest of 5.25% and a history of quarterly losses, including a Q4 loss of $3.4 million.
Negative factors outweigh the positive ones.
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