Sara Martinez Tucker, the federal official in charge of overseeing the student-loan industry, had more than $10,000 invested in student lenders, according to financial disclosure forms filed last October and released to The Washington Post.

The U.S. Department of Education said Ms. Tucker, the No. 3 official at the agency, had not violated any ethics rules because her stock in each of five companies was less than $15,000. Ms. Tucker held $2,745 in Bank of America, $2,597 in Citigroup, $1,923 in Wells Fargo, $1,134 in J.P. Morgan Chase, and $1,615 in Wachovia, according to the Post.

The revelations fuel a growing controversy over how lenders, financial-aid administrators, and government officials do business.

Earlier this month, it was reported that a top official at the Education Department, Matteo Fontana, held at least $100,000 worth of stock in Student Loan Xpress after he joined the department, in 2002. —Jennifer K. Ruark