Borrowers who have a middling credit score, a small down payment relative to the property's purchase price or little equity relative to their home's value will be subject to higher interest rates on so-called conforming loans that lenders can sell to Fannie Mae or Freddie Mac.

The higher interest rates occur because the two government-controlled entities implemented adjustments to their risk-basing pricing structures, effective March 1 for Freddie Mac and April 1 for Fannie Mae.

Borrowers can avoid the higher rates by paying upfront points, suggests Jim Sahnger, a mortgage consultant at FBC Mortgage in Jupiter, Fla. One point is equal to 1 percent of the loan amount.

"Depending on the equity in the house and their credit scenario, they're going to pay a minimum of another quarter point upfront to get the lowest rate or their rate is going to be higher," he says.

Risk-based pricing is a good concept, but the adjustments "send the wrong message," says Fred Arnold, a loan originator and branch manager at American Pacific Mortgage in Santa Clarita, Calif.

"It's going to prevent a lot of people from refinancing or being able to qualify for a purchase," he says.