The invention relates to a composition comprising an organic material susceptible to oxidative, thermal or light-induced degradation and a compound of formula (I-P), (I-O) or (I-M). Further embodiments are a compound of formula (I-P), (I-O) or (I-M), a process for protection of the organic material by the compound, the use of the compound for stabilizing the organic material, an additive composition comprising the compound and a process for manufacturing the compound. The organic material is for example a polymer.