The cost of a college education has been, appropriately, a topic of much discussion recently. While making college more affordable is laudable, enriching company executives and investors at the leading student lender is not.

With tuition increases at most colleges and universities exceeding the rate of inflation for years, these institutions bear a responsibility to control costs. But because applications for admission still far outnumber the openings for the freshman class, colleges have little incentive to hold down costs. Only when applications fall below the available slots for freshmen will colleges have incentive to control their costs.

The other side of the college-cost picture is found in student loans and financial institutions. Most college loans are backed and subsidized by the federal government.

Helping students and their families afford a college education is an appropriate role for the federal government, and most taxpayers don't object to their tax dollars helping to make student loans affordable. But recent news stories surrounding the financial aid industry have been troubling.

Taxpayers should be skeptical about the proposed $25 billion buyout of Sallie Mae, the nation's largest student loan company. Though profit margins on student loans are reportedly thin, Sallie Mae's loans to 10 million borrowers produced a $1.2 billion profit last year — and funded an organization that paid its CEO $19.5 million.

This level of profitability and the $25 billion buyout offer suggest that both the federal subsidies and the interest rates should be cut. And that is exactly what various proposals from the White House and Demo-crats in Congress are proposing.

One of Sallie Mae's many business advantages is that Congress guarantees a certain level of income. But with such highly profitable business and the recent stratospheric buyout offer, Congress should also put a ceiling on profits made on student loans.

If the objective is to make a college education more affordable to more Americans, then the company selling those loans should not be significantly more profitable than other institutions in the financial sector, as Sallie Mae reportedly is.

Other troubling news surrounding student loans concerns an investigation by Andrew Cuomo, attorney general of New York, which discovered that student loan companies often paid fees to financial aid officers and other individuals at colleges to steer student loan business their way.

The massive buyout offer, made by J.P. Morgan Chase, Bank of America and two private equity firms, is further evidence of a stunning, and inappropriate, profit potential in the student loan business.

The proposed buyout should face tough scrutiny because Sallie Mae and the two potentially acquiring banks control 40 percent of the market.

Another downside to a buyout of Sallie Mae is that such a deal would reduce government oversight. Critics of Sallie Mae have found evidence that loan interest rates should be lowered and government subsidies reduced by delving into financial details on profits and executive compensation that the company must provide to the Securities and Exchange Commission. A buyout will reduce that transparency and government oversight.

Commenting on the proposed buyout by the private equity firms and banks, Luke Swarthout, of the U.S. Public Interest Research Group Higher Education Project, said, "They are trying to turn student loans into a black box."

Given the billion-dollar profits at Sallie Mae, the questionable marketing tactics and excessive compensation, less government oversight is precisely not what is needed — if the objective is to provide students with the most affordable financial aid.

Congress is right to challenge Sallie Mae's profits, and to press for cuts to interest rates charged students and to subsidies to the lender.

Extraordinary profits should no longer be tolerated at the student loan giant, which benefits from such a high degree of taxpayer support. Similarly, the proposed buyout should be blocked — unless it benefits student borrowers and taxpayers.