With a figurative flick of a switch, two South Carolina banks that have been chasing loans, deposits and delinquents since the Great Depression officially become one this week.

A financial history through the years

Some notable events in the 80-year history of First Federal:

First Federal Savings & Loan is established on Broad Street in downtown Charleston and opened on May 28, 1934.

First Federal Savings & Loan Association of Charleston is formed as the holding company in 1983. Its stock trades under the symbol FFCH.

First Federal Savings & Loan Association of Charleston changes its name to First Financial Holdings Inc. in 1987. It retains the FFCH ticker.

SCBT Financial Corp. announces that it is buying First Financial Holdings in a stock swap in February 2013. The sale closes on July 26, 2013.

The merged lenders announce in early 2014 they will form a new Columbia-based parent company, South State Corp., and operate as South State Bank.

First Federal branches will reopen as South State Bank on July 21.

For Charleston stalwart First Federal, Friday was the finale. The end of an era.

Come Monday, the largest and oldest homegrown financial institution will change names for the first time in its 80-year history. It will become South State Bank, all the way from the stationery to the signage.

An equally critical transition is taking place behind the scenes this weekend, mostly at the First Federal corporate center in North Charleston. Tech-savvy staffers are working overtime on Mall Drive to ensure a glitch-free transfer of all the local bank's computerized data, from checking account information to loan balances, to the South State digital backbone.

Customers already have been notified about the changes and what they can expect. Among the inconveniences: the online and mobile banking systems for both First Federal and South State are shut down until an undetermined time Monday morning. Branches with Saturday hours were closed.

The next 24 hours, are, in essence, where the rubber meets the road in the First Federal buyout.

"It's really the final step in the transition," said Kellee S. McGahey, executive vice president and director of corporate communications at First Federal.

That shift began in earnest nearly a year ago, on July 26. It was on that date that the owner of First Federal was sold to the former SCBT Corp. in a $447 million deal that stands as the largest combination ever between two South Carolina-based banks.

The purchase also prompted the expansion-minded buyer to unify the new Charleston acquisition with its four other lenders in the Carolinas and Georgia under a new corporate brand. Hence, the South State logo and moniker.

The change, announced and approved this year, reflects the parent company's goal of becoming a regional lending powerhouse in South Carolina and beyond.

SCBT and the three other smaller banks made the switch June 30.

"There's been little to no negative feedback," McGahey said Wednesday.

Now, it's First Federal's turn. Monday's rebranding will mark the end of a homegrown Charleston name that goes back to its opening on Broad Street in May 1934.

In a surprise move, First Federal decided to sell in early 2013, as the industry began to get over its lengthy post-recession hangover. The thinking was that size and scale would be an imperative and an advantage as the banking business consolidates in the years ahead.

The South State logo will be plastered on 135 retail offices in South Carolina, North Carolina and Georgia by 9 a.m. Monday. Odds are, that number will increase.

Much of the heavy lifting from the First Federal purchase has been done, including the closing of overlapping branches. The final big push is to move the Charleston bank's customers to the South State computer system this weekend as seamlessly as possible.

Even before they got together, SCBT, which was started in Orangeburg in 1933, and First Federal became well-acquainted with this back-office dance as they shuffled their way into new markets through mergers and acquisitions.

"Both sides have done this before," McGahey said.

Indeed, South State has put Monday's flick-of-the-switch through three rounds of mock tests to help it identify and anticipate any potential snarls or snags.

The bank also is calling in back-up support, just in case.

"We have dedicated people lined up," McGahey said. "We have many customer care representatives ready to take calls."

Alternatively, First Federal customers with questions or concerns about their South State accounts or loans can get answers the old-fashioned way.

"Branches will be open Monday morning, no matter what," McGahey said.

Editor's note: A previous version of this storry contained an error about the banks' ATMs. They are working this weekend.

Contact John McDermott at 937-5572.