OGH 4 Ob 200/25b | 26.03.2026

Several individuals jointly sold their shares in a limited liability company (GmbH) to a purchaser. The share purchase agreement contained an arbitration clause requiring disputes to be resolved before an arbitral tribunal rather than the ordinary courts. Nevertheless, one of the sellers filed a claim before an ordinary court for part of the purchase price. He argued that the arbitration clause was invalid because other sellers had defects relating to the required form or powers of attorney when concluding the arbitration agreement.

The Austrian Supreme Court (OGH) rejected this argument. The decisive question is whether the sellers constitute a so-called “necessary joinder of parties.” If this is not the case, as the OGH held here, the validity of the arbitration clause must be assessed separately for each individual seller. Consequently, a defect affecting one seller does not invalidate the arbitration clause for the remaining sellers.

Practical takeaway: In M&A transactions involving multiple sellers, the validity of the arbitration clause should be documented carefully for each seller individually. A formal defect affecting one seller does not automatically jeopardize the arbitration clause for the other sellers.