Asset manager and registered investment advisor Fisher Investments, based in Plano, Texas, is selling an interest estimated about 20% to private equity firm Advent International and the Abu Dhabi Investment Authority for between $2.5 billion and $3 billion. The investment, believed to the largest investment in an RIA firm by a sovereign wealth fund, was announced by the firm and reported yesterday by Bloomberg.

In a prepared statement, the company said that the transaction was part of the 73-year-old Ken Fisher's estate planning strategy. Fisher also said his health was excellent and that the firm would continue to operate as an independent business.

The investment values Fisher, which manages $275 billion for an estimated 150,000 individuals and institutions, at nearly $13 billion. Bloomberg News had reported last January that Advent was in talks to acquire Fisher. At the time, both Fisher and Advent denied the reports.

The investment comes at a time when private equity firms are investing in the RIA industry in a big way and, by some estimates are accounting for up to 75% of all investments in the business. Recent reports in the Wall Street Journal and Bloomberg have indicated that private equity firms are experiencing a falloff in investment performance and are finding it challenging to sell, or exit, their investments in the desired timeframe. 

How this plays out for RIA firms remains to be seen. Some observers believe that sovereign wealth funds, with much longer time horizons than most private equity funds, are superior candidates to be long-term investors in the wealth management business.

Fisher founded his firm in San Francisco in 1979. He has described himself as one of the pioneers when it comes to applying price-to-sales analysis as a key metric to evaluate investments.

Fisher Investments is also known one of the most aggressive advertisers and marketers in the asset management world, spending lavishly on television and internet advertising. Some of Fisher's marketing has stressed that the firm is a fiduciary and doesn't accept commissions. Other Fisher ads that have attacked annuities have been perceived in many quarters as negative marketing.