The oil industry recovery has been widely publicized, and its no surprise that it has drawn the attention of the some of the top billionaire money managers in the U.S. According to a report by Bloomberg, billionaire investors Stanley Druckenmiller and George Soros were among those who increased their oil investments in the second quarter of the year.

This information became available earlier this month as a result of 13F filings submitted to the SEC and available to the public. The investments likely paid off, as benchmark oil prices in the U.S. reached a three-year high in July, shortly after the end of Q2.

Duquesne Adds VanEck, Others

Druckenmiller's Duquesne Family Office reportedly bought up 1.68 million shares of VanEck Vectors Oil Services ETF (OIH). This marked the third-largest addition to the office's portfolio for the three-month period ending June 30. Indeed, this was not the only oil product that Druckenmiller bought during that time, either. Duquesne also added the Energy Select Sector SPDR Fund (XLE) as well. Druckenmiller's oil purchases also included companies like Marathon Petroleum Corp. (MPC) and Devon Energy Corp. (DVN). The VanEck stake was valued at $44.1 million, while the Marathon purchase was worth about $34.8 million.

At the same time, George Soros' fund bought up several energy stocks, including Chevron Corp (CVX). Soros Fund Management also bought close to $31 million in shares of Devon Energy last quarter, too.

Oil Rally Continues

Globally, the energy industry has been in the midst of a revival since last year. Prior to that time, crude experienced its worst crash in about a generation. The revival "kicked off in the shale fields of North America last year," according to Bloomberg. Now, the largest oilfield services provider, Schlumberger Ltd., indicates that it anticipates selling out of its services and equipment by the end of the year, thanks to incredibly brisk business.

According to Evercore ISI analyst James West, the rally is likely to continue. "Global oil markets have tightened and oil prices will remain elevated in our view for the next few years," he suggested, adding that "the international inflection point is underway and we believe it has been stronger than anticipated."

It seems likely that investors like Soros and Druckenmiller timed their purchases to generate strong returns on their oil investments. However, a 13F filing does not indicate all of the information about an investor's portfolio. It's possible that either or both of these investors have changed their bets in the energy industry in the time since June 30. The outside world will have to wait until the next round of 13Fs in November in order to see what has happened.