Berkshire Hathaway's Ajit Jain bought about $20 million of stock on Dec. 18, according to a regulatory filing on Thursday.
The move was in A shares, the ones that trade around $288,000 each. The filing said the purchases were done in multiple transactions at prices ranging from $295,750 to $297,000 a share. The move could be interpreted as a sign of confidence as the stock market continued its multi-day plunge to fresh lows for the year.
Shares of Berkshire fell 1.6 percent on Thursday, while the S&P 500 was down nearly 2 percent. Berkshire shares are down 12 percent from their 52-week high amid the broader market sell-off.
Raised in India and a graduate of Harvard Business School, Jain was named vice chairman of Berkshire's insurance operations earlier this year. Warren Buffett has praised him in the past for making a lot of money for Berkshire, and he has been seen as a possible successor should Buffett ever step aside.