The firms of several top investors were busy buying and selling stocks during the second quarter, and CNNMoney.com recently highlighted the moves of three of them.

For starters, Warren Buffett’s Berkshire Hathaway added significantly to its position in Johnson & Johnson, CNNMoney reports. Berkshire also opened a new position in Fiserv, and upped its stakes in Becton Dickinson and Sanofi-Aventis. The firm also sold a chunk of its stake in ConocoPhillips.

Carl Icahn’s hedge fund, meanwhile, added to or initiated stakes in several energy firms. It also picked up shares in the entertainment, gun, and food arenas, according to CNNMoney.

Another hedge fund guru, John Paulson, added to his energy and financial stock positions, with Goldman Sachs among his new holdings.