Federal bank regulators have given the green light to Umpqua Bank and Spokane-based Sterling Financial Corp. to conclude their merger, announced last year.

The first signs of the acquisition will be the replacement of Sterling’s regional signs by Umpqua Bank signs starting the weekend of April 18 and continuing for the next 10 weeks.

A final two-week waiting period ends on April 18. In February, shareholders at both institutions voted overwhelmingly in favor of the merger.

Portland-based Umpqua will gain a financial services foothold in Eastern Washington with the merger. It is considered Oregon’s largest bank.

Umpqua is paying about $1.9 billion in stock for Sterling, the largest financial institution headquartered in Spokane County.

Sterling has around 660 area workers and more than 2,600 across the service area, which includes Idaho, Oregon and California.

It has 176 branches in those states and in Washington.

As of Dec. 31 Sterling Financial Corporation had assets of $10.3 billion.

Reductions in the number of branches where the two banks have overlapping services have not been announced.

Umpqua officials have also not said how many positions will be reduced due to consolidation.

Eve Callahan, who manages corporate communications for Umpqua, said deliberations will continue during the consolidation, which will take at least a few months.

She said Umpqua will be transparent about those cuts.

“We want to get those right,” Callahan said. “We don’t want to speculate and we have deliberately not made any decisions” about jobs or branch reductions, she said.

Merging with Sterling gives Umpqua roughly $22 billion in assets and almost 400 total branches.

“We’ll be the largest community bank on the West Coast and the 34th-largest community bank in the country,” Sterling spokeswoman Cara Coon noted.

The combined companies will operate as Umpqua Holdings Corp., with banking operations conducted under the Umpqua Bank brand.

Sterling CEO Greg Seibly will stay with the company, previous news releases have said.