Billionaire Warren Buffett, marking 60 years leading Berkshire Hathaway, told shareholders in his annual letter released Saturday that he continues to prefer stocks despite a higher cash position.

The mystery over Warren Buffett’s surprisingly defensive stance deepened over the weekend. The 94-year-old CEO of Berkshire Hathaway sold more stocks in the latest quarter and grew a record cash pile even larger to $334 billion,

Investors are poised to study the letter Saturday for insights about the stock market.