Warren Buffett and his company Berkshire Hathaway (BRK.A 0.64%) (BRK.B 0.54%) were once again buying stocks in the second quarter of the year, although not nearly with the same ferocity of the first quarter when they pumped $51 billion into stocks.

Berkshire just released its 13F filing, which shows what stocks the company purchased and sold in Q2, which started April 1 and ended June 30. We knew from Berkshire's second-quarter earnings report last week that Buffett and Berkshire purchased roughly $6.2 billion of equities and sold about $2.3 billion of stocks in the quarter.

Buffett and Berkshire didn't buy anything new but did increase their position in several of their existing holdings. Here are the nine stocks Buffett and Berkshire purchased in Q2.

The three biggest buys

For those who follow Buffett and Berkshire closely, it should come as no surprise that Berkshire significantly increased its position in the Houston-based oil and natural gas company Occidental Petroleum (OXY 0.09%). Buffett has been buying domestic oil companies all year, especially as the tension between Russia and the rest of the world has mounted. The Russian invasion of Ukraine resulted in oil sanctions from countries all over the world on Russian gas, which has led to inventory shortages and higher gas prices.

At the end of the second quarter, Buffett owned roughly 158.5 million shares of Occidental Petroleum, valued at more than $9.3 billion. But since the end of Q2, we know that Buffett has been buying more of the stock and has now accumulated over 20% of the company, or more than 188 million shares. With shares of Occidental closing today at over $64 per share, that values the stake north of $12 billion. Many have surmised that Berkshire's continued buying of the stock could eventually lead to a full takeover of the company.

Berkshire's second big purchase was made in the consumer digital bank Ally Financial (ALLY 6.73%), which specializes in auto lending and which Berkshire first initiated in the first quarter. Berkshire increased its position by 234%, snapping up more than 21 million shares and growing its stake to 30 million shares valued at more than $1 billion. That gives it about a 9.7% stake in the company based on today's closing price. Ally has generated superb returns since the pandemic, thanks to improved operations and elevated car prices, but investors have been concerned about a time when those prices start to normalize.

Buffett and Berkshire also made a fairly sizable addition to their position in the multinational media company Paramount Global (PARA 1.48%), adding roughly 9.5 million shares and putting their overall stake at 78.4 million shares. The position, which is currently valued at more than $2 billion based on today's share price of $26.56, currently makes up more than 12% of the company.

Other notable moves

Buffett and Berkshire also continued to increase their position in some of their largest portfolio holdings, such as their overwhelmingly favorite stock, Apple (AAPL -0.57%). Berkshire added roughly 3.9 million shares and now has 894.8 million shares in the tech giant. This values Berkshire's position in Apple at close to $155 billion based on today's closing price, which represents a nearly 5.7% stake in the company. With Berkshire having roughly $300 billion of equity holdings at the end of Q2, that means Apple made up 40.7% of its equity holdings at the end of the quarter when you exclude Berkshire's $105 billion of cash and cash equivalents.

Berkshire also boosted its large stake in the other large U.S. oil producer, Chevron (CVX 0.75%), by 2.26 million shares. With Chevron closing the day at $156.80 and Berkshire owning more than 161.4 million shares, Berkshire's stake amounts to $25.3 billion or roughly 8.2% of Chevron.

Berkshire then boosted its stake in the video game company Activision Blizzard (ATVI) from 64.3 million shares at the end of the first quarter to more than 68.4 million shares at the end of Q2. Berkshire's stake is now worth roughly $5.3 billion, or nearly 8.5% of the company.

Finally, Buffett and Berkshire added 1.27 million shares of the specialty materials company Celanese Corp (CE 0.08%), about 277,000 shares to the pharma company McKesson Corporation (MCK -1.35%), and more than 47,000 to the insurance and investment company Markel Corp (MKL 0.53%)

Long-term investors who want to follow Buffett's buy-and-hold philosophy could use these timely buys as inspiration, but ought to do their own due diligence to see which stocks make sense in their portfolio.