SEATTLE (AP) — One year after Microsoft announced it was committing $500 million toward affordable housing in the Seattle area, it's upping that by half.

The additional $250 million will provide a line of credit to help the Washington State Finance Commission finance about 3,000 additional units of affordable housing, Jane Broom, the company's senior director of philanthropies, said in a blog post Wednesday.

Microsoft's own success has helped the region boom economically, with Amazon and other tech companies expanding. But as it has, the cost of housing has skyrocketed. Homelessness is a severe concern, and even people with good middle-income jobs, such as teachers and nurses, have been priced out of the cities where they work.

Microsoft announced its $500 million commitment a year ago, saying that much of the money would provide market-rate or below-market-rate loans to developers who want to build affordable housing. Some was also to go toward grants to address homelessness, such as by providing legal help to those facing eviction.

In her blog post, Broom wrote that Microsoft is encouraged by the momentum for addressing homelessness in the region, but that it remains a serious challenge. Data from Zillow, the real-estate website, shows that the Puget Sound region's affordable housing gap is growing, not shrinking: Last year, the area was short 316,000 middle- and low-income housing units, up from 305,000 in 2018.

That 3.6 percent increase was far less than increases of about 10 percent in each of the prior two years — but still an increase, she said.

“While we’re encouraged to see this growth rate fall, it’s clear that what we really need to do is see the housing gap fall, not continue to increase,” Broom wrote.

Microsoft on Wednesday also announced it was making $55 million in investments and grants toward its original $500 million commitment, bringing its total allocated over the past year to $380 million used to support the preservation or creation of over 6,500 affordable housing units in the greater Seattle area.

Some $50 million of the newly allocated funding will go to a new partnership between the Seattle Foundation and the Washington State Housing Finance Commission with support from JPMorgan Chase, the Evergreen Impact Housing Fund. The fund will promote the development of approximately 1,250 low-income housing units east of Seattle.

Broom said Microsoft was pleased to see Seattle and King County last month create a regional homelessness agency, and that the company intends to continue working with mayors in the region to remove zoning and other barriers to affordable housing.