More than six billion credit card offers were mailed to U.S. consumers in 2005, up 16% from 2004, according to Mail Monitor, the direct mail offer tracking service from Synovate. American Express was the primary factor in this increase as the company increased its direct mail credit card solicitation volume by 56% over 2004, but still received responses rates well below the industry’s 2005 average of 0.3%, according to Synovate.

This was more than two times the increase of any of the other top five credit card mailers.

Many other card issuers also significantly increased their mailings. For example, regional issuer Columbus Bank and Trust showed a 205% increase in mail volume from 2004 to 2005. In addition, 58% of credit card offers in 2005 included some type of rebate or rewards program, reported Synovate.