The $44 billion Navy Federal is one among many credit unions seeing a boom in mortgage activity due to falling interest rates.

The country's largest credit union said it had seen a record surge in mortgage applications in the middle part of August, with volume up 50% since the early part of the month. 

But unlike other credit unions which have seen a sharp rise in applications to refinance existing loans, Navy Federal reported that the mortgage volume is split between refinance applications and those to purchase property.

The credit union attributed the surge in large part to a $2,500 credit toward the closing costs for both purchase and refinance loans.

“With mortgage rates again at historical lows, this is a market full of opportunity,” said Jack Gaffney, the 3.7-million member CU's executive vice president for lending.

“We are proud to offer our members extremely competitive rates. We've added these other specials to help our members take advantage of this unique market, knowing that this is one of the most important investments they will ever make,” Gaffney said.

The Virginia-based credit union forecast that the recent surge will wind up lifting mortgage originations at the CU to more than $5 billion, which the CU described as “on par with previous record years.”