Mortgage rates edged higher from a week ago, adding frustration for buyers who are already contending with an unfriendly housing market.

The rate on the 30-year fixed rate mortgage increased to 6.43% from 6.39% the week prior, according to Freddie Mac. While rates have moderated since November when they hovered around 7%, they have been largely stuck in the mid-6% range since the beginning of the year.

Rates add yet another layer of difficulty for buyers, who are also facing inventory challenges, elevated home prices, and — soon — mortgage fee repricing. Meanwhile, homeowners are reluctant to sell, worsening the acute shortage for-sale properties.

"As we enter the typically busy spring season, affordability remains the primary concern in the housing market," Realtor.com Economist Jiayi Xu said.

Upcoming changes to mortgage fees

As potential buyers eye market conditions, Fannie Mae and Freddie Mac are set to update their mortgage fees next month to improve home affordability for riskier buyers.

Overall, the Federal Housing Finance Agency is set to increase fees on conventional loans for borrowers with higher credit scores, while potential buyers with lower credit scores will pay less than before when closing a mortgage. The changes come on May 1.

Often lenders convert those fees into a higher interest rate, and that can add up.

For instance, under the revised pricing system, a home buyer with a credit score of 739 and a down payment of 20% faces a surcharge of 1.25%. That's a half-point more than the previous surcharge of 0.75%, according to Realtor.com. The difference adds an additional $2,000 in closing expenses on a $400,000 loan.

“The new policy could exacerbate the challenges faced by well-qualified buyers, many of whom are repeat buyers,” Danielle Hale, chief economist at Realtor.com, said in a statement. “As these home buyers typically have better credit scores, the revised [fees] are likely to compound their worries along with facing higher mortgage rates.”