Warren Buffett's company has bought nearly 1 million more shares of oil refiner Phillips 66.
Berkshire Hathaway said in a regulatory filing that it owned 80.67 million Phillips 66 shares after the latest purchases this week.
Berkshire now controls 15.4 percent of Phillips 66 stock.
Berkshire has been investing in Houston-based Phillips 66 since 2012. After building up a sizeable stake, Berkshire traded about $1.4 billion of its Phillips 66 stock for an additive business in 2013.
Buffett's company resumed buying Phillips 66 stock when prices became attractive. The most recent purchases were done at prices between $76.77 and $77.65.
The latest purchases made this week are worth roughly $78 million.
Besides investments, Berkshire owns about 90 subsidiaries in a variety of industries, including insurance, utilities, railroads, and manufacturing.