Hancock Holding Co.’s purchase of Whitney Holding Co. pushes the combined company to the No. 3 spot in the area in terms of market share by deposits and the highest number of branches at 40.

Hancock Holding Chief Executive Officer Carl Chaney said the company has not determined how many of the branches will be closed because of duplicated locations or how many people will be laid off at those locations.

However, only a handful of area Whitney and Hancock branches lie across the street from each other. While those locations will be consolidated, very few workers will be affected, Chaney said. The displaced employees will have the first shot at other jobs within the company.

“We’ll end up being a $20 billion company spread across five states ? the 32nd-largest U.S.-based bank in the country,” Chaney said. “When you’re that size, attrition occurs so there are always going to be openings.”

The combined company will have two subsidiaries: Hancock Bank, whose corporate headquarters are in Gulfport, Miss., and Whitney Bank, headquartered in New Orleans, with branches in Louisiana and Texas going under the Whitney name.

The deal gives Hancock Holding $2 billion in deposits, or 13.1 percent of the Baton Rouge metropolitan statistical area’s market share, according to a June 30 report by the Federal Deposit Insurance Corp. JP Morgan Chase Bank is No. 1 with $5.6 billion in deposits, or 36.1 percent market share; and Capital One National Association is No. 2, with $2.6 billion, or 16.8 percent market share.

Chaney said Hancock will look at a number of factors, including traffic count and flow, and the branches’ size, age and location, in deciding which locations to close.

In real estate, location is the key, and in some cases, the Whitney branch is in a better location than the Hancock branch, he said. All of the area branches will end up under the Whitney Bank logo.

Hancock and Whitney will convert to a single operating system in early 2012, allowing customers from both banks to do all their business at branches of both banks. Until then, customers should continue to do business at their current Hancock or Whitney branches. Customers can now use ATMs at Hancock and Whitney without service charges.

Chaney said he’s excited about the opportunities the Whitney acquisition - Hancock Holding finalized the $1.5 billion stock deal this weekend - provides in the Baton Rouge area and throughout the Gulf Coast.

The Panama Canal is being widened and deepened, and every ship, aside from three, will be able to fit through the structure, Chaney said.

“And what’s really interesting is what impact that’s going to have on the port cities along the Gulf of Mexico,” Chaney said. “We are clearly the beneficiaries of this, and places like Baton Rouge are going to see incredible increase in commerce because of the widening of the canal.”

Hancock has branches in every major port city on the Gulf Coast, from Houston to Tampa, Fla., and will be able to facilitate the expected increase in business, Chaney said. Baton Rouge, with its deepwater port and access to rail, interstate and the Mississippi River, is beautifully positioned to take advantage.

The economic impact will be enormous in the port cities, Chaney said. That’s why several of the ports are undergoing major expansions, including Gulfport, Miss., which launched a $1 billion development to compete with Baton Rouge, New Orleans and Houston.