LPL Financial has been the biggest winner by far. "The aggressive growth strategy at LPL Financial is clearly paying dividends," Discovery wrote, adding that LPL still knows how to grow organically and not just acquire. "LPL realized a net gain of 1,532 reps over the three-year period, more than any three other broker-dealers in the industry combined."

But other B-Ds without LPL's size are also gaining. For instance, Invest Financial Corp., the second-largest of the four National Planning Holdings broker-dealers, added 473 reps in 2011 for a net gain (minus departures) of 199. Its total number of reps is now 1,458.

Bill Morrissey, executive vice president of business development at LPL Financial, says the changing needs of consumers are playing a role in advisors' movements, and his firm is taking full advantage of that. Baby boomers have more complex planning needs as they age and need more than just insurance and other related products, and LPL helps its financial advisors meet those needs, Morrissey says. In this environment, they will no longer want to be employees.

"The independent channel is the channel of choice," he says.

LPL has been successful at drawing financial advisors to its network in part because it has 42 external recruiters and 20 internal ones. The recruiting force is divided so it can handle advisors at different revenue levels, such as those with $125,000 to $1 million, those with $1 million to $5 million, and elite advisors and producer groups generating more than $5 million. The recruiting is one-on-one for smaller firms while bigger firms meet with teams, Morrissey says.

At Raymond James, recruits are offered a broad choice of affiliation and business models: They can work as an employee, as an independent or as an RIA. Raymond James Financial Services, the independent broker-dealer with some 3,000 advisors and more than $150 billion in AUM, draws advisors primarily from wirehouses, but also other regional and independent firms.

Raymond James' Investment Advisors division, with about 100 affiliated firms and $7 billion in assets, also attracts advisors from wirehouses and other independent broker-dealers, but appeals more to those seeking total independence and a fee-only model. Though it has yet to approach the scale of the major custodians, the firm is betting that the independent RIA channel will see brisk growth going forward.

"In every case, the advisor [affiliated with Raymond James] retains control over their business with the freedom to manage client relationships their way, with the complete support of a full-service firm. This support starts from the very beginning of their affiliation and includes onsite support from a member of our transition team," says Bill Van Law, president of the investment advisors division.

The company recently announced its successful recruitment of a four-person team from Morgan Stanley Smith Barney to its independent channel.

As part of its practice management package, Santa Monica, Calif.-based National Planning Corporation, the largest of four independent broker-dealers in the National Planning Holdings network, offers the Wealth One platform, which allows advisors who act as wealth managers to offer strategic and tactical solutions for their clients' assets. The platform allows custom portfolio management, including such features as tax harvesting capabilities, reports and block trading, to the individual advisor so that he will not have to develop and support the technology on his own.