WASHINGTON — College students trying to cover the soaring cost of a post-secondary education have more than 3,000 federally qualified lenders to choose from — at least in theory.

At 921 colleges, universities and trade schools last year, a single lender handled the majority of federally backed student loans that help pay for tuition and related expenses.

That has federal officials and student groups concerned that some schools may be improperly steering borrowers to lenders the schools prefer to use, regardless of whether it's the best deal for the student.

Federal education officials sent letters to the 921 schools June 29, reminding them they're barred from pressuring students to choose a specific lender.

"When we see patterns that are troubling, we will act on them," U.S. Education Secretary Margaret Spellings recently said. Such steps could include regular monitoring, fines and, in the worst cases, removal from the federal loan program.

Education officials say the letters weren't based on any evidence of wrongdoing. But probes this year spotlighted unethical behavior by financial aid officers at several schools.

Data obtained by Gannett News Service under the Freedom of Information Act shows the 921 schools that received letters are located in 46 states and two U.S. territories. They range from well-known state institutions to trade schools.

A single lender handled every federally backed student loan at 239 of the schools, mostly smaller career institutions, according to the data. At another 400 schools, a single lender handled between 90 percent and 99 percent of student loans.

Sallie Mae, the nation's largest private provider of federal student loans, topped the list of lenders. Sallie Mae handled the majority of federal student loans at 209 schools in 2006-07 and lent a total $1.4 billion.

Other dominant lenders include: Citibank Student Loan Corp. (75 schools), Bank One (39 schools) and Wachovia Education Finance Inc. (35 schools).

Not everyone agrees that focusing on schools where one lender dominates the loan market is the best approach. Haley Chitty with the National Association of Student Financial Aid Administrators calls the strategy "overly simplistic."

He said most schools already recommend at least three lenders, based on such factors as loan terms, borrower benefits provided and customer service. They have developed such lists because families asked them for help navigating the complex world of loans, he said.

"Market share is not an indication of the loan terms and benefits that students receive," he said. "If a school has five lenders on a preferred lender list and one lender has the best loan rates and borrower benefits, it would make sense that most students chose that lender."

Education officials said they will visit some of the 921 schools that received letters but declined to say why.

Preferred lender lists are designed to ease confusion for students. But they can discourage students from shopping for themselves.

"An 18-year-old incoming freshman who has never borrowed anything before will look at the list and assume it's the better lender to choose from," said Rebecca Thompson, legislative director for the United States Student Association, an advocacy group. "That's often not the case. Students are not being educated about their options."

Most lenders handling federal student loans charge the maximum 6.8 percent interest rate allowed under federal law, said Thompson. Federal loans max out at $5,500 per year. When that's not enough, students often turn to the same lender for private loans because it's convenient. Those private loans can carry much higher rates.

Michael Haynes, a senior at Eastern Michigan University who is carrying $80,000 in student loan debt, said he believes he could have saved money if he'd been less naive and gotten more guidance. He said he relied on the school's lender lists because the process was so confusing.

"I'm still overwhelmed by it. I still don't know how it all works," he said. "I need a financial adviser or a lawyer to know what's going on."

Eastern Michigan is not one of the 921 schools that received a letter from federal education officials.