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). 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."

"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."

"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."

A beneficial owner increased its stake in W.R. Berkley while insiders purchased shares of biotech firms Alumis and Aktis following public offerings. Insider buying often signals confidence because insiders and 10% owners typically buy when they expect share-price appreciation. Insider purchases can be particularly meaningful during market uncertainty and near record highs. The fourth-quarter earnings-reporting season has started, creating trading blackouts for many insiders. Mitsui Sumitomo moved to complete a planned investment in W.R. Berkley, raising its holding to over 51.9 million shares (about 13%), with shares up 14.1% year over year.

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