Berkshire officials don't routinely comment on these quarterly stock filings, and they didn't immediately respond to a request Thursday.
Buffett has said investments smaller than $300 million are likely to be the work of Berkshire's investment managers.
During the second quarter, Berkshire added to its holdings in General Motors Co., VeriSign Inc., USG Corp., Visa Inc., Suncor Energy Inc., Wal-Mart Stores Inc. and IBM Corp.
The nearly 13 million shares of VeriSign that Berkshire now owns gave Buffett's firm ownership of just over 10 percent of the company that manages the databases that house ".com" domain names.
Berkshire reduced its stake in engineering and construction firm Chicago Bridge & Iron Co. by 1.1 million shares. Berkshire held 10.7 million shares at the end of June.
The Omaha-based conglomerate sold some of its DirecTV stock to leave it with 23.5 million shares, down from 34.5 million shares at the end of March.
It reduced its stakes in ConocoPhillips, Liberty Media Corp. and National Oilwell Varco Inc. It also eliminated an investment in Starz Inc.
Berkshire said its shares of oil and gas industry supplier National Oilwell Varco gave it another new holding when NOW Inc. was spun off earlier this year. Berkshire said it held 1.8 million shares of NOW Inc. at the end of June.
Besides investments in companies such as Coca-Cola, Wells Fargo and IBM, Berkshire owns more than 80 subsidiaries in a variety of industries, including insurance, utilities, railroads, retail and manufacturing.