RA Capital Management, L.P. added another purchase to its growing tally of insider buys in Artiva Biotherapeutics, Inc. (ARTV), according to a Form 4 filed with the SEC. On July 31, 2026, the investment firm bought 24,944 shares of the clinical-stage biotech at $9.93 apiece, a transaction worth $247,693.92.
The purchase was made on the open market, meaning RA Capital used its own capital rather than exercising options or receiving a grant. Following the trade, the firm’s indirect holdings in Artiva Biotherapeutics stand at 17,329,570 shares, held through an affiliated entity rather than directly in RA Capital’s name.
A Six-Purchase Buying Pattern
This latest transaction is not an isolated event. It is the sixth open-market purchase RA Capital has made in Artiva Biotherapeutics between July 21 and July 31, 2026, a ten-day window in which the firm has now spent a combined $3,451,817 acquiring shares. Our internal classification tags this activity as a cluster buy, a designation reserved for situations where an insider makes repeated purchases in a short span rather than a single one-off transaction.
The pattern has been building for weeks. As detailed in our earlier coverage, RA Capital Extends ARTV Buying Streak to $3M in Four Days, the firm had already crossed the $3 million mark in purchases by late July, and the July 31 transaction extends that streak further while adding a sixth distinct buy to the sequence.
Cluster buying of this sort — where the same insider steps into the market on multiple separate occasions rather than making one large purchase — has drawn attention from researchers studying insider trading disclosures. Academic studies have found that clustered insider buying, particularly among funds and institutional insiders, can correlate with subsequent outperformance on average, though any individual filing is just one data point and the correlation does not hold in every case.
RA Capital’s continued accumulation in Artiva Biotherapeutics comes as the company’s shares trade in the single digits, and the firm’s total indirect stake now exceeds 17.3 million shares. Whether this marks the end of the current buying streak or another step in a longer accumulation remains to be seen in future filings.
This article is based solely on information disclosed in a public SEC Form 4 filing and is intended for informational purposes as part of our ongoing tracking of insider trading activity.
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Source: original SEC Form 4 filing.