The parent company of LPL Financial Corp., the nation's largest independent broker-dealer, said Friday it filed Form S-1 with the Securities and Exchange Commission in the first step toward becoming a publicly-traded company.

Boston-based LPL Investment Holdings Inc.'s initial public offering could raise up to $600 million. The company said it plans to use the proceeds to repay debt. 

LPL, which also has headquarters in San Diego and Charlotte, says it grew its advisor count to 12,026 as of this year's first quarter, up from 3,569 in 2000. That's a compound annual growth rate of 14%.

In its filing, LPL said its competitive strengths include its market leadership, its ability to serve the mass affluent market, and its ability to serve a broad range of advisor models.

It also cited favorable industry trends such as the growth in investible assets, growing demand for independent financial advice, and advisor migration to the independent model.

In the first quarter ended March 31, LPL's earnings jumped more than 70% on revenue of $743 million, up 16% from the year-earlier period.

If the IPO goes through, the company will trade under the symbol LPLA.

Goldman Sachs and Morgan Stanley will be the offering's chief underwriters, with help from Bank of America/Merrill Lynch and J.P. Morgan.