Insiders say the plug n' play terms were key to the decision that swung the deal to the 1.53-million-sf Downtown trophy at 1717 Main St. The floor had been built out as an executive suites center for London-based Regus Group, which in turn had it subleased to Interactive Business Systems until nine months ago.

The Chicago-based law firm has tapped Matthew D. Orwig to be its managing partner in Dallas and national chairman of Sonnenschein's government litigation and investigations group. The local team is ramping up with former assistant US attorney and cyberlaw specialist, Matthew E. Yarbrough, and one of the nation's leading authorities in employee benefits and executive compensation, T. David Cowart, who hails from the ranks of the fallen Jenkens & Gilchrist firm.

Jones Lang LaSalle senior vice president Marti Nemer and vice presidents Sam Weatherby and Amber Taylor represented the law firm. The 60-story Bank One's long-time broker is Don Dowell, who's moved into the Cushman & Wakefield of Texas Inc. ranks as part of Los Angeles-based Metropolitan Real Estate Investors LLC's February decision about its plans for the high rise, including the leasing assignment.

The word around town is the new firm intends to become a major player in Dallas/Fort Worth's legal circle rather than being an off-shoot set up just to handle a few clients for the Chicago operation. In the world of dealmaking, law firm leases can run the extremes--three to five years for startups or 10 to 15 years for established operations. The Sonnenschein Nath & Rosenthal lease follows the norm as the new team gains traction and builds up ranks--a strategy much like Atlanta-based Powell Goldstein employed last year when it took down 12,000 sf until its local attorneys could make a more permanent decision. Last fall's nod more than doubled the office size, putting the firm into Chase Tower at 2200 Ross Ave. for the long term.

"This is generally how outside firms get established in our market," says Hunter Blanks, the new executive vice president for Colliers International Inc. in Dallas and a leading law firm broker in the city. For three years, law firm leases have been a particularly busy field for Dallas. And, Blanks points out to GlobeSt.com that it's been truly across the board--"growth and expansion with local firms, firm based elsewhere coming here and firms that have split off."

Law firms not only command high-end finish-outs, but building operations also factor into the decision when a deal is at hand because they are not traditional 8 a.m. to 5 p.m. users. Dealmakers know all too well that building efficiencies and operating flexibility for areas like security hours and HVAC settings need to be overcome as part of setting the hook for the prestigious wins.

In the latest cycle, Blanks estimates "40 to 50" renewals and expansions have been struck by the city's existing stock of firms. The next few years, though, are destined to be somewhat quieter because most deals in the past three years have locked the tenants in for at least "six or seven years," he says.