NO longer the exclusive domain of stately Swiss and European institutions, the world's leading private banks are responding to fundamental changes in the foundation of their business - their clients. Traditionally, private banking clients have been well-established individuals with substantial wealth and special banking requirements. These may include a desire to protect and enhance wealth, minimise tax exposure, or consider estate planning - with solutions customised to the situation and confidentiality guaranteed. Today, the nature of private banking has adjusted to serve a new profile of client. This is especially so in Asia. ''They are younger, and more knowledgeable,'' said Robert Simpson, chief investment executive at Chase Manhattan Private Bank, one of the world's largest. ''In Asia, people are accumulating wealth earlier. The traditional, successful entrepreneur client base has dropped in age, while their interest and degree of sophistication in investment alternatives has increased.'' To address this combination, leading private banks, such as Chase, highlight their capacity to offer a full range of investment and traditional banking services and products. These include unit trusts, access to emerging capital markets, and global risk management through derivatives. The expectations of younger clients have also changed. ''They're looking for an institution that can reach across boundaries into global capital markets, position itself to deal with the magnitude of capital flows - and still be flexible enough to perceive and meet clients' needs,'' said Mr Simpson. Despite a change of client profile, the emphasis on the long-term relationship remained. Relationship banking reaches perhaps its most personal level in the area of trusts. A trust is an arrangement by which the owner of assets transfers these to another, a trustee, to be managed in accordance with specific directions, or at the trustee'sdiscretion. Agnes Au Yeung, director and general manager of Chase Manhattan Trust Company, viewed Hong Kong as a prime environment for the trust business. ''Here, we have international families. Everyone travels so much. Wealth is accumulated more quickly in this economic environment. Society, generally, has become more litigious, and a trust is a prudent way of providing against uncertainty.''