Between March 1 and April 30 members of Thrivent Financial for Lutherans will vote on whether to expand their membership bond from being open to only Lutherans to membership open to Christians generally.

“In historical terms this would not be the first extension of our common bond,” Thrivent CEO Brad Hewitt said in a video about the vote on the organization's website. He related how one of the predecessors to the organization had expanded the common bond from one somewhat narrowly defined as a certain kind of Lutheran to one open to all Lutherans.

“And so I look at this as our natural next step,” Hewitt said.

But that next step could also mean sharply increasing the numbers of people eligible to join Thrivent FCU, and that drew a letter from the ABA to the NCUA.

“ABA is concerned that extending Thrivent Financial for Lutherans' common bond to all Christians would be a considerable and problematic expansion of the credit union's membership,” wrote Keith Leggett, ABA vice president and senior economist.

“While Christians may share reasonably similar beliefs, the different and sometimes conflicting doctrinal variations among different denominations suggest that all Christians do not share a meaningful affinity or interaction,” Leggett said.

Leggett also argued that expanding Thrivent FCUs field of membership to all Christians would be the equivalent of making age a sole requirement for credit union membership, an idea, he wrote, that a court has already prevented.

Thrivent has not commented on the letter and NCUA has only said that it has not received any application from Thrivent FCU to change its FOM.

But Leggett called the common bond vote a “backdoor” approach to a significant field of membership expansion and contended the NCUA has the authority to restrict or limit the credit union's field of membership no matter what the sponsoring organization does.