As UnitedHealthcare keeps making investments in tax credits that finance affordable housing projects, the nation's largest insurer also is expanding a program that directly connects homeless people in its health plans with housing.

On Tuesday, Minnetonka-based UnitedHealthcare announced it has hit the $400 million mark in investments in affordable housing since 2011.

Most of the spending generates a financial return for United by way of low income housing tax credits. But the insurer also supports projects that provide housing to people in certain UnitedHealthcare managed care plans who otherwise would be homeless.

"Our work around the homeless members is scaling now," said Dr. Jeffrey Brenner, a senior vice president in UnitedHealthcare's division for health plans with contracts in the state-federal Medicaid health insurance program.

"We've been historically focused on Phoenix and Las Vegas, and have seen a lot of success that we're happy about," Brenner said. "So, we're scaling it up to 15 markets before the end of the year."

Banks, insurers and large financial institutions have invested in low income housing tax credits for many years. The tax credit programs are a key sourcing of financing for the deals, housing advocates say.

For UnitedHealthcare, the tax credit investments come in the context of large health plan reserves that are required by state regulators and routinely are invested in bonds and treasuries. The company has opted to invest some of the reserves in "socially redeeming purposes," Brenner said, via tax credits.

"And then the other side of the company is my side, where the clinical work is going on," Brenner said. "We're finding it to be an important thing to invest in not just good medical care for people, but to round that out with good social care, as well. We're seeing a return on that and good health outcomes, as well."