SEATTLE — Microsoft pledged $500 million to address homelessness and develop affordable housing in response to the Seattle region’s widening affordability gap. Most of the money will be aimed at increasing housing options in the Puget Sound region for low- and middle-income workers at a time when they’re being priced out of Seattle and some of its suburbs, and when the vast majority of new buildings target wealthier renters, said Microsoft President Brad Smith. The pledge is the largest in the company’s 44-year history, and, according to the company, is one of the heftiest contributions by a private corporation to housing, The Seattle Times reported .