By Chris Vellacott and Lisa Jucca

ZURICH, May 26 (Reuters) – Rich bank customers are showing a growing interest in Anglo-Saxon trusts as a way to structure their wealth, but Swiss private banks are reluctant to up their offer as international pressure on tax disclosure builds.

Trusts, a legal concept born in 13th-century England to safeguard the assets of knights leaving for the Crusades, make up an estimated $5-trillion global market and are viewed by lawyers and accountants as a growth area for the heavily pressed Swiss offshore banking industry.

Switzerland, the world’s leading offshore centre, came under attack during the credit crisis by cash-strapped nations seeking to recoup tax revenues and its banks are seeking a new business model while traditional bank secrecy is eroding.

Several Swiss private bankers told Reuters they had noticed an increase in demand by wealthy customers for trusts, which are appealing to clients from emerging markets such as Latin America or Russia as they offer protection from expropriation, forced inheritance laws or expensive divorce settlements.

Trusts — seen by some experts as only worthwile for clients with at least $2 million in assets — can also help reduce a client’s tax burden as the assets are passed on to a third party in a low-tax jurisdiction.