The present invention relates to branched polyethyleneglycol (PEG) derivatives consisting of a molecule with a quaternary carbon connected to three PEG chains, wherein all three PEG chains are of equal length and each comprises 1-30 —OCH2CH2— units, and one group with at least one carbon atom, wherein said at least one carbon atom is attached to the quaternary carbon. Also compositions containing such derivatives and use of such derivatives are disclosed.
