The director of the Pension Benefit Guaranty Corporation (PBGC) is to leave his post in August after four years in the role.

In a letter to colleagues on Friday, Josh Gotbaum said, as he had three children in college, he had promised his wife he would return to the private sector, the Wall Street Journal (WSJ) reported.

Before being appointed to the position by President Barack Obama—and unanimously confirmed by the US Senate—in 2010, Gotbaum had worked for several private, financial institutions.

He was an investment banker with Lazard in New York and London for more than a decade. “He advised businesses, unions, and governments on a diverse range of mergers, acquisitions, and restructurings,” according to PBGC’s website. “Most recently, he was an operating partner at Blue Wolf Capital, helping investors acquire, restructure, and manage businesses.”

After these corporate beginnings, however, he moved into non-profit activities. Between 2001 and 2002, he was the first CEO of the September 11th Fund, a charity with over $500 million in assets. From 2003 to 2005, he led and managed the successful reorganization of Hawaiian Airlines as its Chapter 11 trustee.

In his letter to PBGC colleagues last week, Gotbaum said there remained a lot of work to be done at the organisation.

“Public policy continues to encourage companies to shun lifetime income in favor of lump-sum payments,” the WSJ reported from the letter.  “And PBGC itself remains financially unsound and our multiemployer program is in danger of insolvency.”

Last year, Chief Investment Officer compared PBGC with its equivalent lifeboat for bankrupt company defined benefit plans in the UK—the Pension Protection Fund (PPF)—in a two-part series.

It found PBGC was struggling in some areas as often its hands were tied by legislation.

For example, the PBGC cannot set its own premiums. For years, the level set was far too low for the liabilities being covered by the pension fund, but it requires an act of Congress to push through any amendments.

In 2003, the US Government Accountability Office added PBGC to its “High Risk” list of agencies, because it controls neither the benefits it pays nor the premiums it charges.

“Congress has repeatedly raised PBGC’s premiums, but they remain too low to fund our obligations. That’s why, 10 years later, we remain on GAO’s High Risk List,” the 2013 PBGC annual report said.

However, at the end of last year, these premiums were hiked. The Bipartisan Budget Act 2013 pushes for a big rise in premiums for single-employer corporate pension plans, making PBGC premiums one of the largest costs of maintaining a DB plan, according to Bob Collie, chief research strategist for Russell Investments’ Americas Institutional.

“PBGC premiums will overtake investment management fees in many cases,” said Collie. “Plan sponsor resentment of the PBGC—which was already high—may become irreparable.”