Flame retardant formulations comprised of at least one bromine-containing polyol are produced by a process which comprises: A) heating a mixture formed from components comprised of (i) tetrabromophthalic anhydride, (ii) at least one aliphatic polyol, and (iii) at least one liquid straight chain aliphatic diester of a straight-chain alkane dicarboxylic acid to form an intermediate composition; and B) contacting all or a portion of the intermediate composition one or more times with (iv) at least one alkylene oxide that results in the formation of a liquid product formulation, and optionally, removing any excess alkylene oxide present; the amounts of (i), (ii), (iii), and (iv) used being proportioned to form a formulation having a bromine content of at least about 40 wt %, a viscosity at 25.degree. C. of about 20,000 cps or less, and an acid number as determinable by aqueous sodium hydroxide titration and expressed in terms of potassium hydroxide, of less than about 1 milligram of KOH per gram of the formulation.