The leader of Nationstar Mortgage Holdings’ (NSM) servicing operations is stepping down.

Nationstar’s president and chief operating officer, Harold Lewis, informed the company Wednesday that he intends to retire and will resign from his positions, effective May 31.

Lewis has been with Nationstar since 2012. According to his bio on Nationstar’s website, Lewis came to Nationstar from CitiMortgage, where he was chief operating officer. Lewis joined CitiMortgage in 2009.

Prior to that, Lewis held executive positions at Fannie Mae for seven years, including as senior vice president of national servicing. Lewis has also held senior management roles with Resource Bancshares Mortgage Group, Nations Credit, Bank of America/Barnett Bank, Cardinal Bank Shares and Union Planter National Bank.

According to Nationstar, under Lewis’ watch, the company’s servicing portfolio grew from approximately $100 billion in unpaid principal balance in early 2012 to around $390 billion in unpaid principal balance at the end of the first quarter of this year.

Nationstar CEO Jay Bray will add the title of president when Lewis steps down.

Filling the role as the head of company’s servicing operations will be Mike Rawls, who is being promoted to executive vice president of servicing. Rawls is a 15-year veteran of Nationstar.

Recently, Rawls led the company’s default servicing business, and more recently has been responsible for reverse mortgage servicing and the company’s non-performing loans segment.

Lewis’ departure comes on the heels of Nationstar posting a surprising loss in the first quarter, driven somewhat by a loss of servicing revenue.

The company’s first-quarter servicing segment revenue of $109 million fell 49% from Q4, mostly due to higher prepayments as rates fell, the company said earlier this month.

Those results led several analysts to downgrade the company. Analysts from FBR Capital MarketsOppenheimer and Barclays (BCS) issued significant reductions to Nationstar’s price targets, and in one case, a downgrade from “market perform” to “underperform.”

FBR Capital downgraded Nationstar from “market perform” to “underperform,” and lowered its price target from $25 to $15. According to a note, FBR said “they continue to view (Nationstar) as the best high-touch, specialty servicer that remains well positioned to make further mortgage servicing rights acquisitions.”

But the FBR analysts cautioned that Nationstar is “transforming into a more traditional mortgage bank that suffers from mortgage servicing rights asset-related earnings volatility, as this quarter demonstrated.”