Dan Arnold speaks at LPL's 2017 Focus event in Boston.

LPL Financial confirmed industry speculation on Tuesday, saying it has bought National Planning Holdings’ four broker-dealers: National Planning Corp., Invest Financial, Investment Centers of America and SII Investments.

While LPL has about 14,300 advisors and $540 billion in assets, the four NPH broker-dealers have about 3,200 advisors with $120 billion of assets — putting the combined group at 17,500 reps and $660 billion in assets. LPL Financial is a self-clearing and custody firm, while three NPH BDs rely on Pershing and one on Fidelity.

The deal was signed and closed Tuesday, following regulatory approval, according to LPL, which is based in Boston, San Diego and the Carolinas.

“The demand for financial advice continues to grow, and the independent model is the fastest-growing part of the industry,” said LPL President & CEO Dan Arnold, in a statement. “We are committed to being a leader in our core markets, so we are excited to announce our purchase of NPH, which brings us together with one of the largest U.S. independent broker-dealer networks.”

The initial purchase price was $325 million, though LPL says it could pay up to $123 million more for the four BDs in the first half of 2018, based on how much of the advisors’ revenues move onto LPL’s platform.

No contingent payment would be paid, however, if less than 72% of the advisors’ production (fees and commissions revenue) is onboarded, “and the amount of the contingent payment increases on an interpolated basis for onboarded production in the range of 72% to 93.5%,” it explained in a press release.

LPL will “onboard” the former NPH advisors and client assets onto its platform rather than integrating NPH’s operations into its existing business; NPH will maintain its operations during the onboarding period.

The “two waves” of advisor movement should be wrapped up by March 31, 2018, the IBD says.

“Given the similarities in LPL’s independent model to the NPH model, we believe LPL is the ideal acquirer to ensure continuity of the quality service and support for our clients and their financial advisors,” explained Scott Romine, president and CEO of NPH, in a statement.