Warren Buffett, the renowned investor and CEO of Berkshire Hathaway, has recently disclosed a confidential stock pick that the conglomerate has been quietly accumulating. The chosen stock is the insurer Chubb, with Berkshire Hathaway acquiring nearly 26 million shares of the Zurich-based company, amounting to a stake valued at $6.7 billion.

Chubb, a property and casualty insurer, now stands as Berkshire’s ninth largest holding as of the end of March. The revelation of this significant investment caused a surge in Chubb’s stock price, with shares rising by almost 7% in after-hours trading. Year-to-date, Chubb’s stock has seen a 12% increase.

Notably, Chubb itself has an interesting history, having been acquired by Ace Limited in 2016 for $29.5 billion, leading to the adoption of the Chubb name by the combined entity. Evan Greenberg, the current CEO of Chubb, is the son of Maurice Greenberg, the former chairman and CEO of insurance giant American International Group.

Berkshire Hathaway, headquartered in Omaha, has a strong presence in the insurance sector, with investments ranging from auto insurer Geico to reinsurance company General Re, as well as various home and life insurance services. In 2022, Berkshire also completed the acquisition of Alleghany for $11.6 billion.

Interestingly, Berkshire had managed to keep its accumulation of Chubb shares under wraps for multiple quarters, obtaining confidential treatment to shield the details of its stock holdings from public view. This secrecy surrounding the investment had sparked speculation within the financial community, with many anticipating a potential bank stock acquisition due to Berkshire’s increased equity holdings in the financial sector.

It’s worth noting that Berkshire’s decision to keep such a significant purchase confidential is relatively uncommon, with the last instance being the undisclosed acquisitions of Chevron and Verizon in 2020.