MetLife is looking to increase investments in apartment buildings in U.S. cities such as New York and Los Angeles as young professionals fuel demand.

“We would love to do more multifamily, and we’ve been very active,” said Robert Merck, the head of MetLife Real Estate Investors. “The demographics look good going forward for multifamily.”

MetLife, the largest U.S. life insurer, is turning to real estate to bolster profits and support long-term obligations amid low bond yields. Apartment demand is climbing, with fewer Americans owning their homes more than six years after a housing slump contributed to the longest and deepest recession since the Depression.

The firm boosted lending for commercial real estate 19 percent last year, to a record $11.5 billion, and agreed to take ownership stakes of $1.9 billion in such properties. It also has been developing a business that invests in real estate for clients such as SunTrust Banks and Norway’s sovereign-wealth fund, adding to fee income.

“There’s a lot of capital around the globe looking for yield,” Merck, 55, said. “Core real estate has proven to be a good, solid long-term investment.”

MetLife held $40.9 billion of commercial mortgages in December, up from $40.5 billion a year earlier. About half were linked to offices, 23 percent to retail buildings and 9 percent to apartment complexes. The New York-based insurer’s $488.8 billion portfolio is mainly invested in bonds.

The insurer owns investment properties, mostly consisting of offices, that it valued at $13.6 billion as of Dec. 31. Its holdings of apartments climbed 27 percent, to $2.2 billion, last year.

Competition from banks and ­government-sponsored enterprises limited multifamily lending, Merck said. Loans on those buildings fell 6.9 percent, to $3.7 billion at the end of the year.

The homeownership rate in the United States slid to 65.2 percent in the fourth quarter, from a high of 69 percent in 2004, Census Bureau data show. The figure is lower among people in their 20s and 30s. Rents climbed 3.2 percent last year, though the pace was faster in markets such as Seattle and New York, according to data from Reis Inc.

American International Group chief Robert Benmosche, 69, cited an increasing number of renters as his firm looks to add investments in apartments.

Apartment-building values recovered more quickly from the crisis than other commercial property. Prices for the dwellings are 5.8 percent above pre-crisis levels, while total commercial-property prices remain below 2007 highs, according to the Moody’s/RCA Commercial Property Price indexes.

Amid the competition, MetLife is developing apartments from the ground up, leasing them out and collecting payments. That strategy can be more profitable over time, Merck said.

That’s the approach MetLife took with one of its best-known real estate investments. After developing the Stuyvesant Town and Peter Cooper Village apartment complex in the 1940s, MetLife owned the New York property for six decades before selling it for $5.4 billion in 2006.

MetLife typically targets higher-end properties in such cities as New York, Los Angeles, San Francisco and Seattle, Merck said. The company is benefiting as more people become “renters by choice” after the housing crash, he said.

“The psychology of a lot of folks is that they’re not looking to buy houses for investment anymore,” he said.

Merck said MetLife is planning to expand a real-estate partnership with Norway’s sovereign-wealth fund and is looking to work with investors on more commercial-mortgage deals. The firm invested in commercial property in Washington, San Francisco and Boston in a $1.7 billion joint venture with Norges Bank Investment Management.