Warren Buffett's company reveals its mystery bet is a nearly $7 billion stake in insurance giant Chubb

• Warren Buffett's secret stock is Chubb, an insurance giant.
• Berkshire Hathaway quietly built a 6.4% stake in under nine months, worth $6.7 billion as of March.
• Buffett and his team also slashed their biggest stock bet, Apple, by 13% last quarter.

Warren Buffett has finally revealed his company's mystery stock: Chubb.

The famed investor's Berkshire Hathaway first bought into the insurance giant in the third quarter of 2023, but secured regulatory permission to keep the holding confidential until it finished building its stake.