It may be the CEO's favorite business, but Wells Fargo & Co.'s wealth management unit is not growing.

Choppy markets in the fourth quarter cut revenue 5 percent to $3.51 billion at the San Francisco-based bank's top fee-generating business. The unit offers mutual funds and other investment products, and serves a range of clients from those with more than $50 million in assets served by its Abbot Downing brand to mass market consumers.

In the brutal revenue environment since the financial crisis, Wells Fargo and other banks have turned increasingly to wealth management to boost returns.

But because of competitive pressures, tougher regulations and ever shakier markets, that strategy has produced less-than-sterling numbers at Wells.

Rough Sledding

Barclays analyst Jason Goldberg has estimated that Wells rivals Morgan Stanley and Bank of America Corp.'s Merrill Lynch, also will post wealth management revenue declines when they report quarterly results on Tuesday.

Rafferty Capital Markets analyst Dick Bove said he expects wealth management to be "one of the businesses that'll do most poorly over the next couple of years" at banks.

Wells CEO John Stumpf does not share that view. At a December conference hosted by Goldman Sachs, he called the wealth investment management division the bank's "biggest opportunity."