Markin took his profits from 1929 and continued to expand, purchasing Yellow Cab of Chicago and the Parmalee Transportation Company, which ensured that there would be future buyers of Checker Cabs in two major markets, Chicago and New York.  Markin’s purchase of the Yellow Cab Chicago taxi fleet operation was a major setback for GM, as all future cabs purchased by Chicago Yellow Cab would now be Checkers not the GM produced Yellows.

Profits for 1929 were also invested in a new Checker taxicab, the Model M introduced in 1931. A continuation of the town car theme, the Model M was quite a striking vehicle. Visually the car possessed some interesting styling cues, mainly vertical rectangular headlamps and “sugar scoop” fenders to protect tyres in minor accidents. Additionally, the Model M had rear passenger only running boards continuing the town car theme. Style wise, the Model M looked at home parked next to Cadillac and Lincoln town cars.

The Model M utilized a smaller, 122-inch wheelbase, was powered by the Buda J-216 and was equipped with the first electric taximeter, jointly developed by Checker and Pittsburgh Taximeter Company. Both the Model M and Model K were available in 1931.