Wells Fargo Bank has widened its lead in the South Florida deposit market by gaining more than $5 billion of area deposits since last year, and several other big banks are hustling to close the gap.

JPMorgan Chase Bank, in particular, is pursuing a rapid South Florida expansion that added 19 branch offices and about $2 billion of deposits during the year ended in June, enlarging its branch network in Miami-Dade, Broward and Palm Beach counties to 159 locations, and counting.

“We have one opening up next week. We have a couple of others that are under construction and should be done before the end of the year,” said George Acevedo, regional manager of retail operations in Florida and Georgia for JPMorgan Chase Bank. “When you look at 2013, we have another seven planned for Miami and probably another five or six, give or take, for Broward. … We’re committed to making sure that we are the most convenient bank in town.”

But New York-based JPMorgan Chase and other big banks in South Florida are still chasing a market-leading share of deposits that San Francisco-based Wells Fargo controls.

Wells Fargo increased its No. 1 share of South Florida’s deposit market to 18.3 percent at the end of June from 16.3 percent a year earlier, according to the Federal Deposit Insurance Corp. Its area deposits grew during the 12-month period to $30.8 billion from $25.8 billion.

FDIC data also show that Bank of America ranked second in the South Florida deposit market at midyear with a 14.9 percent share, followed by Citibank (7.6 percent), SunTrust (6.4 percent) and JPMorgan Chase Bank (6.2 percent). The five banks collectively controlled 53 percent of all South Florida deposits at midyear, up from 51 percent a year earlier.

JPMorgan Chase added almost a full percentage point to its South Florida market share, and Citibank gained more than half a point. Both Bank of America and SunTrust lost about a half point.

Wells Fargo boosted its number-one share of the South Florida deposit market by 2 percentage points despite closing about a dozen area branches since the summer of 2011, when it completed the conversion of systems and signage at the old Wachovia National Bank branches that it acquired in 2008.

Wells Fargo may extend the size of its South Florida branch network by adding a few new locations next year, net of closings. “We have several locations we’re expecting,” said Frank Newman, the South Florida regional president of Wells Fargo.

Newman said lower unemployment and higher real estate values are signs of that the South Florida economy is improving. “We think there’s going to be very solid growth in our consumer business and our small-business customer base,” he said. “There’s been pressure on the construction and the government sectors. But we feel housing is improving,” along with certain segments of commercial real estate market.

Wells Fargo has closed some leased locations in South Florida rather than renew expiring office leases on unfavorable terms. “We had several situations where we couldn’t agree with the landlord on a lease renewal, a 10- or 20-year lease renewal,” Newman said. The bank has faced some branch overlap, too, so “in many cases, we find it’s necessary to consolidate a store because we have another one very close by.”

FDIC data show that, during the 12 months ended June 30, Wells Fargo reduced its branch count by three in Palm Beach County, three in Miami-Dade County and five in Broward. But Wells Fargo also has been hiring more staff at the rest of its South Florida branch offices, or “stores,” which now total 201.

“We have added more bankers in all of our store locations, so we’ve got more bankers talking to more prospects,” Newman said. Next year, “we plan to add easily 100 new jobs in South Florida to our franchise.”

Asked if competition among banks was increasing in South Florida, Newman said many rivals are trying to recruit Wells Fargo’s employees and not just its customers, making talent retention a top priority. “You can tell there is activity in the market for talent,” he said. “We want to hold onto the bankers we have.”

Not all of five leaders in the deposit market have saturated South Florida with branch office locations. Bank of America had 208 branches in the tri-county area at midyear, more than any other bank. Wells Fargo, SunTrust and JPMorgan Chase had another 462 between them.

Yet Citibank had the third-largest share of the deposit market at midyear despite its comparatively small network of 53 branches in South Florida. The bank will open its 54th area branch in December at the intersection of Fifth Street and Jefferson Avenue in South Beach.

One way Citibank is holding onto South Florida depositors is by offering them some freedom from fees at a time when many banks are trying to increase their non-interest income. “We are not charging customer to use debit cards. We don’t charge customers to use the teller,” said Kathryn Chase, regional president for the East Coast at Citibank. “You can lose your market share by your actions, or you can gain market share by your actions … We still fight it out every day for customers.”

Will a South Florida-based bank ever rank among the top five in the area’s deposit market? One candidate is BankUnited, which held 3.74 percent of all South Florida deposits on June 30, the sixth-largest share of the market.

But the Miami Lakes-based bank is nearing the end of its planned branch-network expansion in Florida. BankUnited has 96 locations in 15 Florida counties and may not expand much beyond 100, chairman, president and CEO John Kanas said last week.

“Our theory on deposit-market share has always been the same. … We are not consumed with the idea that we have a large market share in a particular market,” Kanas said Oct. 25 on a conference call with stock analysts to discuss the bank’s third-quarter financial performance.

“We really concentrate on profitable deposit-market share, rather than market share in general.” Kanas said. “We’re not chasing deposit growth with rates.”