The merger, which will be finalized Jan. 1, will combine the forces of Harborstone and Prevail, which has its headquarters in Seattle, and branches in Issaquah, Seattle, Woodinville, and Tukwila.
Harborstone has branches in Puyallup, Lakewood, Gig Harbor, Bonney Lake, Lacey, Fife, and Tacoma.
The merger was previously approved by each credit union's board of directors, the State of Washington, and the National Credit Union Administration (NCUA), and Prevail members approved it Oct. 19.
With the merger, Prevail members will gain business banking services, which they have not previously had, and Harborstone customers will become part of credit union shared branching, which allows credit union members to conduct business at credit unions outside of their home locations.
Together, the new Harborstone Credit Union will boast 70,000 members, 17 locations, and assets of $1 billion, according to a press release from Prevail.
Prevail told members in a press release that though the merger will be effective Jan. 1, it may be several months after that before they see significant changes, including new signage at current Prevail branch locations.
Representatives of both credit unions have previously emphasized that both are healthy, saying the merger is a way to offer their members more. Prevail had net income of $951,008 in 2011, a 206.47 percent increase over 2010, and total assets of $235 million, according to its most recent annual report. Harborstone had total assets of $757 million in 2012, according to its most recent annual report.