Berkshire Hathaway Inc. raised its stakes in Amazon.com Inc. and two U.S.-based banks during the second quarter, according to a regulatory filing.

Warren Buffett, the company's chairman, president and CEO, previously said he typically shied away from big technology investments. In May, he announced Berkshire's play in online retail behemoth Amazon, disclosing that he was not the one who pulled the trigger on the investment.

Berkshire upped its share count in Amazon during the quarter by more than 11% to 537,300. The move brought the value of Berkshire's holdings in the retailer up 18% to $1.02 billion.

Berkshire added to its stake in Bank of America Corp. with the purchase of 31,081,000 shares in the second quarter, building its holdings up by 3.47%. The company also boosted its shares of U.S. Bancorp by 2.4%.

Berkshire cut its holdings in Charter Communications Inc. by 4.97%, selling 284,102 shares in the second quarter. No new companies were listed in the portfolio.