Heading off a costly rate increase for returning college students, a bipartisan group of senators reached a deal Wednesday that would offer students better rates this fall but perhaps assign higher rates in coming years.

The deal would offer students lower interest rates through the 2015 academic year but then rates were expected to climb above where they were when students left campus this spring. Undergraduates could face rates as high as 8.25 percent, while graduate students would see rates as high as 9.5 percent and parents' rates would top out at 10.5 percent.

(Read more: What New Student Loan Rates Mean For You)



The deal was described by Republican and Democratic aides who insisted on anonymity because they were not authorized to discuss the ongoing negotiations by name.

A vote on the agreement could come as early as Thursday, although it could be pushed back to the middle of next week depending on the Senate calendar.