The S & P 500's oil and gas sector has risen by nearly 30% this year while the broader market has sold off. And those bumper returns appear to be reversing a decade-long trend: They've now started to attract investors who had largely shunned the sector amid the clean energy push in the past decade. Investment research group Morningstar's data shows energy stocks were 11% of its Global Equity Index a decade ago. And by late 2020, the sector was just 3% of the index. But that trend has started to reverse. Here's a selection of funds that Morningstar says have recently bought oil and gas stocks. GQG Partners Global Equity Morningstar's report suggests Rajiv Jain, who runs the fund, is "the most notable energy bull." His fund has increased its exposure to oil and gas by 10 times since March 2021, when it made up just 2% of the portfolio. According to Morningstar analyst Jonathan Miller, the fund manager said he believes that production has not kept up with demand and expects prices to remain elevated for longer. ExxonMobil , Occidental Petroleum and Petrobras are three of the fund's top picks. The fund has returned 9.5% over the past year, while its benchmark index has declined by more than 10%. Miller, however, noted that Jain is an "outlier" with his outsized, positive position in the sector. Ninety One Global Strategic Mark Breedon from the company is another fund manager who recently added ExxonMobil to his diversified portfolio. Breedon said he believes ExxonMobil is focused on shareholder returns by selectively investing in specific projects. According to Morningstar, Exxon appears to be investing only in energy-transition projects in which the company has engineering expertise, such as blue hydrogen and carbon capture and storage. Exxon is one of Ninety One Global Strategic Equity Strategy's top five holdings, making up 3.3% of its fund. BlackRock BGF World Energy It's not just the diversified funds that are making significant moves within the energy sector, however. BlackRock's energy-focused fund has repositioned itself, favoring European stocks over North American ones. That's because the team behind the fund expects that European demand for non-Russian energy sources will rise in the coming months, which will in turn benefit its chosen stocks. London-listed Shell and BP make up nearly 14% of the $2.8 billion fund. According to Morningstar, fund managers Mark Hume and Alistair Bishop favor higher-quality oil producers like them, which they expect will deliver better results in a "stronger for longer oil and gas price environment." A 'completely missing' picture Shares in nearly all oil and gas companies have fallen over the past three months following a decline in crude oil prices. Brent crude has fallen below $85 a barrel after a drop in demand from China as it continues with its "zero-Covid" policy. Fears of a recession in the United States are also weighing down on the commodity. However, one analyst said that while oil prices have fallen to reflect the long-term "doom and gloom," they have not yet priced in the short-term increase in demand expected in the coming months. "Everything is pointing toward a rather bullish picture," said Victor Katona, lead crude oil analyst at the consultancy Kepler. "But that is just not reflected in the oil price. It is just completely missing." Katona expects OPEC+, the group of oil-producing nations, to cut production in its upcoming meeting to increase crude prices by 15% to 20%. "I think the natural corridor for oil prices will be somewhere between 90 and 100 [U.S. dollars per barrel] because that's the corridor with which most of the oil producers will be satisfied, especially in the Middle East," he added. Why have funds avoided oil & gas in the past? According to Morningstar, fund managers have mostly shunned the sector in light of environmental concerns . Morningstar's Miller said some fund managers have invested in companies that they think have improved their environmental, social and governance credentials. He said: "We see some positives with a ESG lens for Exxon, having responded to calls to bring in more outside voices to its board and announcing emissions reduction targets." "The firm also invests in low-carbon technologies — but each of these efforts is measured and keeps oil and gas production at the core." "So much so, they think this strategy is unlikely to win praise from environmentally oriented investors."