On Wednesday, Microsoft announced it is committing $500 million to address the lack of affordable housing in the greater Seattle area—the sixth most expensive region in the country.

The company will lend $225 million at below-market interest rates in an effort to subsidize the preservation and construction of middle-income housing in six cities around Seattle: Bellevue, Kirkland, Redmond, Issaquah, Renton, and Sammamish. Twenty-five million, delivered in the form of philanthropic grants, will be used to combat homelessness.

The remaining $250 million will support low-income housing across King County, which encompasses Seattle and is the most populous county in Washington State. “We believe that additional capital at market lending rates can help accelerate the construction of low-income housing across the region,” wrote Microsoft president Brad Smith and chief financial officer Amy Hood, in a post on the company’s blog.

Since 2011, housing prices in the tech giant’s hometown have surged by 96 percent, thanks to job growth outpacing housing construction. Median income has failed to keep up with rising housing costs, “increasingly making it impossible for lower- and middle-income workers to afford to live close to where they work,” write Smith and Hood.

“Teachers, nurses, first responders and many in key roles at nonprofits, businesses and tech companies now begin and end their workdays with long commutes,” Smith and Hood continued. “And people who are homeless face problems that are even more daunting.”

The company is also pushing the state legislature to enact policy changes, including the appropriation of $200 million to Washington State’s Housing Trust Fund, to expand support for very-low-income individuals and families.

Microsoft’s pledge, which is the largest contribution in the company’s history, comes after Microsoft recently announced that it would expand its Redmond headquarters to make room for 8,000 more employees.

Watch: The Voices Behind Microsoft’s $500-million Affordable Housing Initiative

Video courtesy Microsoft