HOUSTON—On the occasion of its 30th anniversary this year, Natural Gas Partners (NGP) is sticking to its long-term investment strategy of following a buy-and-build business model, often taking public its portfolio companies when it can.

The model apparently works pretty well for the Irving, Texas-based private equity (PE) firm. It never lost money in its first 11 PE funds for energy. NGP Energy Capital Management has $20 billion in commitments from limited partners and is raising its 12th fund. The last one, NGP Natural Resource Fund XI, closed in January 2015 at $5.3 billion.

“This is still a vital industry. A lot of money is to be made and good careers built,” said Tony Weber, managing director and chair of NGP’s executive committee, speaking recently to the Houston Producers Forum.

“The key is: how do you direct your capital, beat the competition and stick in the most straws?” he said, speaking of the tremendous opportunity in the Permian Basin where NGP has back several large companies.

However, Weber could’ve been speaking about any U.S. play. Over time, the firm has backed 358 management teams. Because of that track record, NGP’s partners and 60 employees enjoy a broad network of industry contacts in most plays.

“We typically make smaller commitments per company, yet we have more companies in the portfolio than some of our peers. We’re the first money in and the last money out, so the rock has to be good,” he said.

NGP’s gross returns since 1988 are about 30%, “right at the top of the group” of PE players, he said.

About half the teams that NGP backs are repeat customers.

In May one of NGP’s portfolio companies, Boaz Energy II, took public a new trust, PermRock Royalty Trust (NYSE: PRT).

Some of its other, larger successful IPOs included Rice Energy Corp., RSP Permian Inc. (NYSE: RSPP), Centennial Resource Development Corp. (NASDAQ: CDEV) and Parsley Energy Inc. (NYSE: PE). In another example, NGP sold a portion of its shares in WildHorse Resource Development Corp. (NYSE: WRD) in an IPO in 2016 yet remains the company’s largest stockholder with a 58.8% stake or 59.5 million shares.

“As a result of these IPOs, we essentially now have a $3 billion, long-only hedge fund because we hold so much stock,” Weber said.

Weber also spoke of a youth movement underway today at NGP as the firm transitions from its founding partners, Ken Hersh and David Albin, to a new generation. As a result, the firm has started what it calls the Leaders Under 40 Initiative.

“About five years ago we decided we’d take about 10% of our money and place it with much younger people, and commit it in smaller amounts like $50-, $60- or $70 million,” he said. “As it turns out, many of these teams have had a better return than the gray hairs. We’ve actually formed 21 companies with CEOs under 40 since 2014.”

Weber joined the company in 2004 after 14 years in commercial banking and a stint as CFO of Dallas-based Merit Energy Co.

Leslie Haines can be reached at lhaines@hartenergy.com.