In Art & Law 2022, Anne Laure Bandle wrote a chapter on art auction price guarantees in which she analyses the contractual arrangements of such guarantees provided by auction houses or third parties. The chapter also assesses the extent to which such guarantees are regulated by law, in particular with regard to competition law.
 
In essence, Swiss law does not have any specific rules governing the matter of auction price guarantees. Nonetheless, a legal framework exists that auction houses need to comply with. According to contractual law and competition law, financial interests should be disclosed in order to prevent any deceptive influence on the auction process. Bidders should be aware that a guarantee agreement exists with the auction house or a third party and what it means. Consequently, the auction catalogue should reflect the person of the guarantor. In order to eliminate potential distortions of competition, it may also be necessary to disclose the amount of the guarantee. Finally, hammer prices communicated by an auction house should express the actual amount owed, i.e. take into account any “discounts” granted to the winning third-party guarantor. 
 
Find her analysis in the recently published book Kunst & Recht 2022 / Art & Law 2022, Stämpfli.droit , edited by Beat Schönenberger and Peter Mosimann.