Berkshire Hathaway's big bet on airlines has paid off.
The conglomerate's holdings of four major airlines gained $174 million on Thursday morning from their closing prices on Wednesday, based on stock holding disclosures from recent filings with the Securities and Exchange Commission.
An SEC filing in May showed Warren Buffett's conglomerate owned tens of millions of shares of American Airlines, Delta Air Lines, United Continental and Southwest Airlines. Berkshire Hathaway added millions of additional shares of American and Southwest stock between filings in February and May.
The value of Berkshire's American Airlines shares rose $71.5 million on Thursday morning, opening more than $1.40 above the close price on Wednesday. American shares spiked after the company disclosed that Qatar Airways has signaled its intention to acquire a 10 percent stake.
As of its disclosure in May, Berkshire Hathaway held 49.3 million shares of American Airlines stock. It added 3.7 million shares since the beginning of the year.
Berkshire's Delta holding rose $39 million since the market close on Wednesday. Berkshire owned 55 million shares as of the end of the first quarter. Its 28.9 million United shares rose $23 million. And its 47 million Southwest shares rose $40.9 million.