Berkshire Hathaway, led by Chairman Warren Buffett, disclosed a significant investment in the insurance company Chubb, valued at approximately $6.7 billion. The revelation came in a Wednesday filing with the Securities and Exchange Commission (SEC) detailing the company’s first-quarter investments. Berkshire Hathaway acquired nearly 26 million shares of Chubb, representing a 6.4 percent stake.

The investment had been kept confidential as Berkshire built its position, utilizing “confidential treatment” from the SEC. This approach has been used by Buffett in previous investments to avoid revealing strategic moves prematurely.

Following the announcement, Chubb’s stock surged by over 8% in after-hours trading. This jump aligns with a common market reaction to disclosures of Berkshire’s investments, as many investors follow Buffett’s portfolio decisions closely.

Buffett’s latest investment aligns with Berkshire Hathaway’s established focus on the insurance sector, which includes subsidiaries like Geico, National Indemnity, and General Re. This disclosure also aligns with a recent trend where Berkshire has increased investments in financial entities while reducing stakes in consumer products.

In addition to Chubb, Berkshire Hathaway has made several noteworthy portfolio adjustments. Recently, the conglomerate sold off 10 million shares of Apple and 80 million shares of HP. Despite these sales, Apple remains Berkshire’s largest investment.

Overall, Berkshire Hathaway’s portfolio remains extensive, including interests in railroads, utilities, and various manufacturing and retail companies. The company’s cash and equivalents stood at $189 billion as of the end of March.