Huge Insider Buying Now at This Insurance Giant and 2 Biotechs

In the past week, a beneficial owner has continued to build a stake in insurance giant W.R. Berkley Corp. (NYSE: WRB | WRB Price Prediction). And public offerings of shares of biotech firms Alumis Inc. (NASDAQ: ALMS) and Aktis Oncology Inc. (NASDAQ: AKTS) also brought insiders to the Buy window.

Though these were the most prominent insider purchases in the past week, there were a handful of other notable ones as well. Let’s take a quick look at these transactions.

Is Insider Buying Important?

What does insider buying tell us?

A well-known adage reminds us that corporate insiders and 10% owners really only buy shares of a company because they believe the stock price will rise and they want to profit from it. Thus, insider buying can be an encouraging signal for potential investors. This is especially so during times of market uncertainty, and even when markets are near all-time highs.

Note that the fourth-quarter earnings-reporting season has begun, so many insiders are prohibited from buying or selling shares. Below are some of the most notable insider purchases that were reported recently, starting with the largest and most prominent.

W.R. Berkley

• Buyer(s): 10% owner Mitsui Sumitomo
• Total shares: more than 1.3 million
• Price per share: $67.57 to $69.76
• Total cost: almost $92.3 million

Last spring, this buyer reached an agreement to acquire 15% of W.R. Berkley’s shares. Mitsui Sumitomo expects to complete its investment in this Connecticut-based insurance holding company during the first quarter of 2026. Its stake is up to more than 51.9 million shares, or over 13%.

The share price was last seen within the buyer’s latest purchase price range. Yet, the stock is marginally lower than six months ago because of recent volatility due to profit-taking. But note that shares are up 14.1% year over year, outperforming the S&P 500 in that time. Analysts are cautious, with only four out of 18 of them recommending buying shares. The mean price target of $72.31 is 6.5% higher than the current price but less than the recent all-time high of $78.96.

Mitsui Sumitomo is a massive Japanese financial conglomerate. Note that it also recently acquired an 18% stake in MassMutual’s Barings.

Aktis Oncology

• Buyer(s): 10% owner MPM BioVentures 2018 and three directors
• Total shares: more than 4.4 million
• Price per share: $18.00
• Total cost: almost $79.3 million

This Boston-based clinical-stage oncology company raised over $318 million in its recent initial public offering, intended to fund the clinical development of its two leading drug candidates and for general corporate purposes. Eli Lilly and Co. (NYSE: LLY) is a strategic investor and a collaborator.

The share price has been dropping since the stock began trading and was last seen about less than two dollars higher than the offering price, in a post-IPO range of $19.02 to $29.16. About seven analysts cover the stock, and they have a consensus Hold rating.

The beneficial owner above has a stake of more than 10.2 million shares, or approximately 26.2% of the company. The collaboration agreement with Lilly is valued at over $1.1 billion.

Alumis

• Buyer(s): two directors
• Total shares: about 1.0 million
• Price per share: $17.00
• Total cost: nearly $17.0 million

These buyers took advantage of a public offering of common shares after Alumis stock surged following the recent announcement of positive trial results for its next-generation plaque psoriasis treatment. The $345 million raised is intended to support the development and potential commercialization of its drug pipeline.

The share price of this clinical-stage biopharmaceutical company based in South San Francisco are 115.7% higher than a month ago, as well as 40.4% higher than the offering price. Wall Street sees plenty more room to run to the consensus price target of $37.29. That would be an all-time high. All eight analysts covering the stock recommend buying shares. Morgan Stanley and Wells Fargo are among analysts that recently maintained Buy-equivalent ratings.

Note that both of these directors were return buyers. They also acquired shares back in November and December.

And Other Insider Buying

These were not the only notable insider purchases of the past week. Here is a quick look at some others.

Some smaller insider buying was reported at ACV Auctions, Agree Realty, Neogen, nVent Electric, Park Hotels & Resorts, S&P Global, Strategy, STAAR Surgical, and Strive, as well.

Mitsui Sumitomo Continues to Build WR Berkley Stake