Thrifty - Thrifty and Dollar same company?

I have never rented with any other company but Alamo so pardon me if I am not familiar with these 2 companies. Are they basically the same company? I got great rates with both Thrifty and Dollar for our California trip! Now i need to decide which company to go with as the rates are within $ 10 of each other.

They both are part of Dollar Thrifty Automotive Group. All other things being equal, I generally select Thrifty - in my experience, they have seemed to be marginally better at crediting FF miles.