Wealth management services are exploding in the Washington area, where at least four financial firms have expanded their offerings in the past four months.

Last week, for instance, Bank of America said it hired 35 financial advisers in the greater Washington area in recent months to cater to customers with assets worth between $50,000 and $250,000. The hires are part of a nationwide effort that has doubled the number of advisers to more than 1,200 in the past year.

The bank, which has 8 million of these customers nationwide, also rolled out its Platinum Privileges rewards program in the area. The program provides “preferred” customers with higher interest rates on accounts, greater access to specialists, fee waivers and discounts on home loans, said Aron Levine, a managing director and preferred business executive at Bank of America.

“This client base is the fastest-growing segment of the economy and has been fairly underserved by the industry,” he said. “Metro D.C. is an important market in catering to this group, which is why we will continue to expand in 2012.”

Financial services firms have mined Washington for affluent customers for a long time, but the effort intensified as area wealth continued to grow, albeit marginally, despite the sluggish economy. Household incomes in Loudoun County, for instance, rose 2.8 percent to $119,540 in 2010, according to Census Bureau data.

“D.C. has changed dramatically. It was always a high employment town because of the government and real estate, but it turned into a tech center, which created a lot of wealth,” said Steve Lockshin, founder and chief executive of Convergent Wealth Advisors.

The Potomac-based firm in late October started a division, called Independence by Convergent, dedicated to clients with $500,000 to $5 million in assets. Convergent traditionally manages money for clients with at least $10 million in assets, but now is targeting a demographic that Lockshin said he believes has growth potential.

“People are paying a lot more attention to their portfolios now because of the volatility in the markets. They are very conscious of the fact that they need to take risks to grow their assets but are afraid of suffering losses,” he said. “We wanted to democratize our core business because technology now allows us to deliver a similar offering to smaller clients.”

Expansion for some wealth management firms has meant acquiring teams in the area or simply putting down roots to serve existing clients.

HighTower, a Chicago-based financial services company serving high-net worth individuals, rolled up the Leventhal Group in Bethesda in September and District-based Pagnato-Karp Group in July. Meanwhile, Northern Trust, a Chicago-based bank targeting clients with at least $5 million in assets, opened a District office in early October to be closer to its local customers.

“We have hundreds of clients here,” said Joanie Stringer, managing director of Northern Trust’s District office.

Northern Trust is well known in the wealth management world, but it is hard to gauge what impact it, or any of its competitors, will have in an increasingly saturated market.

“It is a tough market for financial services,” Stringer said. “But there is no better time to grow our business.”