NEW YORK (AP) ¿ Shares of for-profit companies offering college-level courses fell Tuesday after Congressional leaders vowed closer scrutiny of the sector, which is the object of a critical government evaluation.

Rep. George Miller, D-Calif., who heads the House Education Committee, said Monday after the market closed that a Government Accountability Office report on so-called proprietary schools is "extremely troubling and warrant(s) further examination by Congress."

The GAO report, released earlier this week, found loan default rates of students who receive Title IV money to attend proprietary schools exceed the default rates of students who receive federal money to attend conventional college-level institutions.

The report found that many proprietary schools admitted unqualified students who had a greater tendency than other students to drop out, let students stay enrolled despite a lack of academic progress and also misrepresented themselves to prospective students.

Miller expressed concern that proprietary schools may be "gaming the system to admit more students ¿ students who may not be fully ready for college and may be more likely to default on their federal student loans.

"It's clear that at a minimum, greater oversight is needed to ensure that those for-profit institutions that are flouting the law are held accountable to their students and the public," he said.

His panel's Subcommittee on Higher Education, Lifelong Learning, and Competitiveness plans hearings on the GAO findings, according to the subcommittee's chairman, Rep. Ruben Hinojosa, D-Texas.

In midday trading, shares of ITT Educational Services Inc. fell $6.35, or 5.5 percent, to $109.26, Bridgepoint Education Inc. declined 52 cents, or 2.9 percent, to $17.23 and Apollo Group Inc. gave up $3.04, or 4.1 percent, to $71.70.

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