The invention relates to a phosphoric acid ester and salts thereof of the general formula (I), wherein A is a monohydroxyl residue derived from C1-C20-alkyl-(AO)x-OH or Acyl-(AO)x-OH; or C1-C20-alkyl-(AO)x-(HA)y-OH or Acyl-(AO)x-(HA)y-OH; or C1-C20-alkyl-(AO)x-(AA-AO)y-OH or Acyl-(AO)x-(AA-AO)y-OH; or MO-(HA)y-OH or MO-(AA-AO)y-OH; wherein Acyl is an aromatic carboxylic acid residue or a saturated or unsaturated fatty acid residue; AO is a polyC2-C4alkyleneglycol residue, HA is a hydroxycarboxylic acid or a lactone thereof, AA is a dicarboxylic acid, MO is a monoalcohol, x is 1 to 250, y is 1 to 250, B is a mono-, di-, or tri- or polyhydroxy di-, tri or multi-carboxylic acid residue which is linked via the hydroxy group to the phosphoric acid and via one of the carboxylic acid groups to the monohydroxyl residue [A], the remaining carboxyl acid group(s) is/are free or is/are esterified with a further monohydroxyl residue [A], resulting in branched esters; n is 1-2; m is 1-4. The phosphoric acid esters are used as wetting agent or dispersants.