Houston ranks No. 1 on a list – but it's not something to exactly celebrate. The Bayou City is leading major Texas markets in its volume of sublease space on the market, according to a report from Newmark Grubb Knight Frank. Houston ended 2016 with 11.5 million square feet of available sublease space. Dallas finished the year with 5 million square feet of sublease space, and Austin with a mere 1.6 million square feet, according to the report.