With mortgage loan rates remaining at historically low levels last week, the mortgage industry could see the refinance boom continue despite a new fee assessed on lenders.

Fannie Mae and Freddie Mac implemented the “adverse market refinance fee” on Dec. 1, a 0.5 percent fee assessed on lenders when selling the loan to the government-sponsored enterprises. Citing uncertain economic conditions related to the pandemic, Fannie and Freddie had announced the fee in mid-August, originally scheduling it for Sept. 1.

But with just a few weeks’ notice, the mortgage industry protested the timing of the fee, noting that borrowers had already locked in rates on loans that would not close until after Sept. 1. The fee’s effect on low-income borrowers was another concern.

The Federal Housing Finance Agency, which oversees the GSEs, in late August delayed the fee’s implementation until Dec. 1, while also exempting refinance loans with balances below $125,000, nearly half of them for lower-income borrowers at or below 80 percent of area median income, according to the FHFA. Affordable refinance products, including Fannie Mae HomeReady and Freddie Mac Home Possible, were also exempted from the fee.

“The fee is necessary to cover projected COVID-19 losses of at least $6 billion at the Enterprises,” the FHFA said in August. “Specifically, the actions taken by the Enterprises during the pandemic to protect renters and borrowers are conservatively projected to cost the Enterprises at least $6 billion and could be higher depending on the path of the economic recovery.”

Because the fee is assessed on lenders, it does not show up in the borrower’s closing costs but is reflected instead in the loan’s price. Lenders planning to pass the fee onto borrowers likely began adjusting their pricing models in October or November when locking in rates for loans that would not close until Dec. 1 or later, said Patrick Boyaggi, co-founder and CEO of Own Up, a Boston-based mortgage technology company that helps consumers shop for and secure mortgages.

Boyaggi said he initially saw miscommunication that the consumer would directly pay the fee directly. Instead, it resulted in about one-eighth of an increase in rate.

Even with those adjustments, mortgage rates remain at historic lows. Freddie Mac reported last week that the 30-year fixed-rate mortgage averaged 2.71 percent for the week ending Dec. 10. A year ago, the 30-year rate averaged 3.73 percent. The 15-year fixed-rate mortgage averaged 2.26 percent last week compared to an average of 3.19 percent a year ago.

This low-rate environment has minimized the effect of the fee, Boyaggi said.

“I don’t think we’ve seen this fee have a material impact on consumers, especially when you think about people refinancing below 3 percent for a 30-year fixed rate mortgage, and in many cases doing so without paying any closing costs,” Boyaggi said. “I think consumers are seeing this as still a tremendous opportunity to refinance and to create their own personal stimulus by reducing the expense of their mortgage.”