BB&T Corp. is buying the 78 branches of BankAtlantic, along with its deposits and healthy loan portfolio, for about $5.4 billion.

BB&T, based in Winston-Salem, N.C., says the deal will expand its footprint in South Florida and add to earnings immediately, minus acquisition costs.

The agreement calls for BB&T to acquire $2.1 billion in loans and roughly $3.3 billion in deposits, for a premium of about $301 million, or 9 percent of deposits. The exact premium will be based on deposits at closing, but will not be higher than $316 million.

BB&T is not buying BankAtlantic's non-performing assets, typically loans that are past due and considered in danger of default.

BB&T shares dropped 41 cents, or 2 percent, to $22.93 in premarket trading. BankAtlantic shares more than tripled to $7.99.