The 343,528-sq.-ft. building has a long-time lease with the social media giant. : (Bloomberg)—A real estate fund backed by Brookfield Asset Management Inc. is buying an office in a Seattle suburb leased to Facebook Inc., a sign that commercial-property markets are thawing for some buildings after the pandemic put a chill on deals. The buyer is paying $365 million for the 343,528-square-foot (31,915-square-meter) building, called Block 16, according to a statement to be released Friday.