The super-rich are being wooed by Wall Street advisers who want to help them manage their millions. Today's market is brimming with multimillionaires, but more specifically an emerging group known as "Pentamillionaires," or individuals with at least $5 million in investable assets. Experts attribute the surplus to the 1990s bull market, which created a generation of multimillionaires. Managing the assets of the affluent is not an easy roll to fill. Advisers must compete against a host of competitors in the wealth-management business, including insurers, accounting companies, mutual funds, and Internet firms. What is more, advisers are entering the wealth-management field at a time when sweeping regulatory changes are underway. There are also drawbacks to going after wealthy clients. With less than 1 percent of the American public fitting in this category, keeping wealthy customers happy may be more difficult. Also, the loss of one well-to-do client may dramatically affect an adviser's income stream.