Transwestern has reportedly struck an agreement to purchase storied Chicago brokerage MBRE as the Houston-based real estate giant seeks to grow its leasing and management portfolio of downtown office towers.

The deal, first reported by Crain’s Chicago Business and based on an email from an MBRE executive to a client, would see Transwestern take over leasing at MBRE-managed properties like Michigan Plaza, 550 West Washington Blvd. and 181 West Madison St.

Transwestern already handles leasing for several large downtown office properties of its own, including NBC Tower, The National and 77 West Wacker Drive.

There has been a wave of consolidation among brokerage and management companies in recent years as global investors increasingly demand one-stop shop service providers.

Newmark, for one, has been making “bolt-on” acquisitions of smaller firms and broker teams across the country and in Europe,  while earlier this year, Colliers agreed to acquire a majority interest in Denver-based Versus Capital. CBRE last year purchased a majority interest in program and project management firm Turner & Townsend.

Both Transwestern and MBRE declined to comment on the sale to Crain’s, and the terms of the deal were not immediately available.

MBRE bills itself as “the most successful privately owned commercial real estate company in Chicago” and was founded in 1982 as Miglin-Beitler Management. It merged with a New York venture of real estate investors Howard and Edward Milstein in 1998 and was rebranded as MB Real Estate in 2002.