DoubleLine LLC received regulatory permission on Wednesday to be a financial adviser, nine days after being founded by Jeffrey Gundlach, TCW Group Inc.’s former investment chief.

The Los Angeles start-up received approval from the Securities and Exchange Commission to open investment funds, said Gundlach, who was fired from TCW in a management shake-up earlier this month.

“The approval has occurred on a timeline that will allow us to continue to welcome, without interruption, those many clients with whom we have developed relationships of great personal trust and confidence over the years,” Gundlach said in a statement.

The firm plans to launch its DoubleLine funds early in 2010, Grundlach said. He told Bloomberg News that the firm could have $50 billion under management by the end of next year.

Gundlach started DoubleLine with financial backing from L.A.’s Oaktree Capital Management LP, whose chairman, Howard Marks, is a former TCW manager. About 40 of 65 investment professionals at the fixed-income group managed by Gundlach at TCW have left for DoubleLine since its founding.

Some investors also have left the company. Market researcher Morningstar Inc. said the TCW Total Return Bond Fund had $12 billion under management before Gundlach left, but its assets had fallen to $6.6 billion as of Dec. 22.

TCW on Dec. 4 acquired rival firm Metropolitan West Asset Management LLC and installed its managers to run the fund after relieving Gundlach of his duties.