In a letter sent yesterday to the Federal Trade Commission, U.S. Sens. Charles Schumer (D-N.Y.) and Mark Warner (D-Va.) requested that the agency turn its attention to digital ad fraud and its detrimental economic impact.

The letter, addressed to FTC chairwoman Edith Ramirez, cited a January 2015 study that found 88 to 98 percent of ad-clicks on major ad platforms were fraudulently generated by automated bots. “Bots plague the digital advertising space by creating fake consumer traffic, artificially driving up the cost of advertising in the same way human fraudsters can manipulate the price of a stock by creating artificial trading volume,” the letter reads.

Expressing concern that rampant ad fraud will result in consumers paying more for goods and services, the Senators proposed greater oversight of the online ad industry, and requested that the FTC answer a series of questions about the criminal practice, including what steps the agency is taking to stop it.