Flame retardant and stabilizer combined, for polyesters and polyamides

The invention relates to a flame retardant and stabilizer combined for thermoplastic polymers, which comprises, as component A, a phosphinic salt of the formula (I) and/or a diphosphinic salt of the formula (II), and/or polymers of these, where R1 and R2 are identical or different and are C1-C6-alkyl, linear or branched, and/or aryl; R3 is C1-C10-alkylene, linear or branched, C6-C10-arylene, -alkylarylene, or -arylalkylene; M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and/or a protonated nitrogen base; m is from 1 to 4; n is from 1 to 4; x is from 1 to 4, and which comprises, as component B, at least one chain extender from the following classes of compounds b1) bislactams, b2) bisoxazolines or bisoxazines, and/or b3) epoxides, b4) anhydrides of polybasic carboxylic acids.