Since buying Merrill Lynch & Co., BofA overtook UBS AG for the spot, according to the study of 248 institutions by Scorpio Partnership (see “Bank of America Buys Merrill Lynch“). According to a Bloomberg report about the results, BofA managed $1.5 trillion at the end of 2008 compared with $1.39 trillion at UBS. Citigroup Inc., came in third and Wells Fargo & Co. also climbed the ranks to fourth after purchasing Wachovia Corp. (see “Wachovia Leaves Citigroup at the Altar“).

Since the end of 2008, Citigroup’s Smith Barney and Morgan Stanley merged (see “Morgan Stanley Smith Barney is Born“), which is not represented in the data.

The wealth management industry certainly took a hit in 2008. The financial crisis caused a loss of clients assets in the wealth management industry by 16% to $14.5 trillion, Scorpio said. Wealth managers hired 6% more staff but saw an 8% loss of income.

“Assets are going down and the number of millionaires isn’t increasing,” Scorpio Managing Partner Cath Tillotson told Bloomberg. “It’s worrying that we’ll potentially see a slash-and-burn reaction once banks realize that the net new money isn’t there for them to chase.”

Here are the world’s biggest wealth managers and their assets under management, based on the 2008 data from Scorpio:

1. Bank of America Corp.: $1,501 billion
2. UBS AG: $1,393 billion
3. Citigroup Inc.: $1,320 billion
4. Wells Fargo & Co.: $1,000 billion
5. Credit Suisse Group AG: $612 billion
6. JPMorgan Chase & Co.: $552 billion
7. Morgan Stanley: $522 billion
8. HSBC Holdings Plc: $352 billion
9. Deutsche Bank AG: $231 billion
10. Goldman Sachs Inc.: $215 billion.