OneWorld Germany-ORD business I/D €1322
No seasonal restrictions, bookable only via (O)TA e.g. Expedia, not with the airlines directly. Base fare about €900 + €400 YQ and taxes. Great availability in summer/fall/Christmas on AA, BA, IB and AY. ORD appears to be the only U.S. destination, but some open jaw returns from some other U.S. cities are also possible for a few hundred more.