Focus Financial Partners announced today it acquired WESPAC, an Oakland, Calif.-based registered investment advisor and benefits administrator with more than $1 billion in assets. Focus Financial, an international network of wealth management firms that's based in New York, now has 16 partner firms with more than $29 million in assets. The deal closed on July 1, and terms weren't disclosed.

WESPAC provides financial planning and advisory services to individual clients, as well as retirement and benefit plan administration and investment services to small- and mid-sized companies.

Earlier this year, Focus Financial expanded overseas when it acquired Greystone Financial Services, a RIA based in Manchester, England. In July, Focus helped Greystone buy Roger Harris & Co., a wealth manager in Leicestershire, England.

"Sub-acquisitions are an integral part of Focus's strategy to add value to our partners," said Focus Financial founder and CEO Rudy Adolf.

Focus Financial's strategy centers on acquiring advisory firms with assets of at least $350 million. It generally purchases between 40% to 70% of a firm's cash flow in exchange for cash and an ownership stake in the company. In return, Focus Financial provides various support ranging from back-office and technology to marketing and business development. Its partner firms have more than 18,000 clients. It eventually hopes to go public.

Focus Financial began two years ago with four firms and $3.5 billion in assets, and was funded by the private-equity group Summit Partners.