RA Capital Management, L.P. added another purchase to its recent run of open-market buys in Artiva Biotherapeutics, Inc. (ARTV), according to a Form 4 filed with the SEC. On July 24, 2026, the investment firm bought 41,319 shares at $9.99 apiece, a purchase worth $412,776.81.
Following the transaction, RA Capital’s indirectly held stake stands at 17,283,802 shares, held through an affiliated fund or entity structure rather than in the firm’s own name directly. That indirect ownership designation is common for investment managers whose positions are held on behalf of funds they manage.
Part of a Broader Buying Pattern
This is not an isolated trade. The July 24 purchase is the fourth in a series of open-market buys by RA Capital between July 21 and July 24, 2026. Across those four transactions, the firm has now put roughly $2,996,091 into ARTV shares in less than a week. Our classification system flags this kind of repeated, back-to-back buying activity as a ‘cluster buy’ — a pattern that stands out from a single, one-off purchase because it shows sustained conviction over several trading days rather than a single decision made at one point in time.
We covered an earlier stage of this same buying streak in a previous piece, RA Capital’s $2.58M Buying Streak in Artiva Biotherapeutics (ARTV), when the running total was closer to $2.58 million. With this latest filing, the cumulative figure has grown to just under $3 million.
For readers searching for the underlying SEC form for insider trading disclosures like this one, Form 4 filings are the standard mechanism through which officers, directors, and large shareholders — including institutional investors like RA Capital — report changes in their holdings within a couple of business days of a transaction.
Why Clustered Buying Draws Attention
Academic research on insider trading patterns has generally found that clustered buying, where multiple purchases occur in a tight window, tends to correlate with modestly better subsequent stock performance compared to isolated single purchases. That said, this correlation is a statistical pattern observed across large datasets, not a guarantee tied to any individual company or filing. This article is a factual account of a public SEC disclosure and is not investment advice; readers should not interpret it as a recommendation to buy or sell shares of Artiva Biotherapeutics or any other security.
Investors keeping an eye on top insider buys often watch for repeated activity from the same filer over a short period, since it can indicate how a sophisticated holder is positioning around a specific company at a given price level — in this case, shares purchased at just under $10 each.
Source: original SEC Form 4 filing.