Depressed scores raise the interest rates and fees that are quoted by mortgage lenders at application. Sometimes, the higher rates lead to monthly payments that are hundreds of dollars higher than they should be.

The three suits charge that, under the federal Fair Credit Reporting Act, the national bureaus -- Equifax, Experian and TransUnion -- are required to follow "reasonable procedures to assume maximum possible accuracy of information in consumer (credit) reports."

William A. Harris Sr. of Greenville County, S.C., in his complaints, states that each of the bureaus allows credit card giant Capital One to withhold the credit limits on its customers' card accounts -- knowing full well that such omissions frequently lower consumer credit score calculations.

Credit industry experts say lenders withhold limits as a way to discourage raids on their customer lists by competitors who have access to national credit files. Cardholders with lower apparent scores may be less desirable to other creditors sifting through national bureau data in search of prospects.

The suits, filed in U.S. district court in Greenville, S.C., shed light on a controversial behind-the-scenes practice that may be more commonplace than many consumers are aware. Harris' lawyer states that "when Federal Reserve Board researchers examined 310,000 individual credit files two years ago, they found that fully 46 percent of all consumers were missing at least one credit limit."

Consumers who are new to the credit marketplace or have relatively few cards or other credit accounts typically are hurt the most. That's because the most widely used credit scoring system in the mortgage field -- Fair Isaac Corp.'s FICO score -- gives heavy weight to a consumer's "utilization" of his or her available credit. The higher the usage of credit relative to the limit, the lower the score.

In his suits, Harris charges that Capital One's "standard policy of not reporting has a substantial adverse impact on consumers. It makes it appear that many, if not most, Capital One credit card customers have used up more of their available credit than is actually the case, thereby lowering their credit scores."

Equifax, Experian and TransUnion know the potentially negative effects whenever a creditor withholds credit limits. The bureaus "have systematically violated the (law) by failing" to require Capital One to report all card members' limits.

Capital One is not named as a defendant in the suits. Under the prevailing, voluntary credit system in this country, no federal law requires it, or any other lender, to report any client's data to any bureau. However, federal law does require the credit bureaus to strive to be accurate, and Harris' suit argues that Equifax, Experian and TransUnion are not in compliance.

The lawsuit seeks to represent any person who believes their credit score was limited by credit card agencies.