We're hearing reports of soaring rents in high-end downtown Austin rental buildings like the Monarch, Ashton, and AMLI. In one case, a tenant's recent renewal resulted in a 30% increase in the market rate and the elimination of concessions. In total, this meant a rent increase of more than 50%.While downtown rental properties struggled to find tenants a few years ago, all of the major buildings are now full. Vacated units are re-leased with amazing speed -- turnovers now average just a few days between tenants. With many new residents and few new units, supply and . . .