Described is a hybrid yarn consisting of at least two varieties of filaments, at least one variety (A) having a lower heat shrinkage and at least one variety (B) a higher heat shrinkage than the rest of the filaments of the hybrid yarn, wherein the first variety (A) of filaments has a dry heat shrinkage maximum of below 7.5%, the second variety (B) of filaments has a dry heat shrinkage maximum of above 10%, and its dry heat shrinkage tension maximum is so large that the total shrinkage force of the proportion of the second variety of filaments is sufficient to force the lower-shrinking filaments present to undergo crimping, the optionally present, further filament varieties (C) have dry heat shrinkage maxima within the range from 2 to 200% and at least one of the filament varieties (B) and/or (C) is a thermoplastic filament whose melting point is at least 10.degree. C., preferably 20.degree. to 100.degree. C., in particular 30.degree. to 70.degree. C., below the melting point of the lower-shrinking component of the hybrid yarn. Also described are a process for producing the hybrid yarn and the use of the hybrid yarn for producing permanent deformation capable textile sheet materials and fiber reinforced shaped articles.