For those who wonder how college tuition costs manage to keep rising year after year, apparently defying laws of economic gravity, Sewanee, a liberal arts college in Tennessee, has an answer: they can’t.

On Wednesday, Sewanee announced that it will cut its $46,000 annual bill for students by 10 percent in the fall.

The college, formally Sewanee: The University of the South, is betting that the drop in tuition  which at this point it can afford  will help it compete on two fronts: with the public universities that are siphoning off a growing share of the students it accepts, and with other private colleges where tuition is likely to increase by 4 to 5 percent this year, as it has for the last two years.

“The university has made a bold and perhaps risky move,” said John M. McCardell Jr., who became vice chancellor of Sewanee a year ago. “But given the realities of higher education in the current economy, we believe that some college or university needed to step up and say, ‘Enough.’ ”