Posted by 
This type of deposits is specific to Switzerland. It consists in giving a mandate to a (swiss) bank to place a deposit outside from Switzerland in the name of the client. Thanks to this offshore placement, Fiduciary deposits are not subject to a local withholding tax, compared to any other interest product (current accounts, term deposits, bonds, notes…). This kind of deposits is only subject to a commission taken usually at maturity/renewal time. A fiduciary deposit can be at fixed term or at sight (call notice, usually 2 days notice). For fixed terms, you can specify an automatic renewal, consisting in renewing every x month(s) either the initial capital or both capital plus interest. A client may give specific instructions to the bank, in order to allow placements only to listed counterparts, or to avoid some countries.
Legally speaking: interest rate given to the client should be exactly the same as the rate of the related placement (no spread allowed). Fiduciary comes from a Latin word that means trust: of course you need to trust the bank you’ve given the deposit!
The bank is legally not responsible for the funds as they are placed offshore.
This type of deposits may be an opportunity to place in some countries where base rates are quite high (Turkey…), with limited risks: in practice, a swiss bank will place money to low-risk counterparties only , as its reputation is involved despite the strict & legal responsibility rules.