The Verge | GM adds monthly service to Maven Seeking Alpha General Motors (GM +1%) says the Maven program is now offering a monthly service called Maven Reserve in Los Angeles and San Francisco. The progam is expected to be expanded to other markets later this year. Maven Reserve allows customers 28-day ... GM will now let you 'share' a car for a whole month, parking and ... General Motors' Maven launches monthly car plan | VentureBeat ... GM's Maven lets you rent cars for up to 28 days - Engadget |