The highly anticipated Association of National Advertisers report looking into rebates and other nontransparent practices in the advertising business finally dropped on Tuesday, and it’s threatening to really sour the rosé ahead of the annual ad confab in Cannes this month.

As CMO Today reports, the eight-month-long probe detailed “pervasive” shady practices in the U.S. ad industry, namely where agencies accept cash rebates from media companies for spending a certain amount, with those agencies’ clients “unaware of any rebates being returned.” While the 58-page report is certainly revealing, it raises even more questions: which specific agencies are the worst offenders? Will marketers audit or ditch their agencies? Did anyone break the law? For their part, the major ad holding companies have criticized the ANA for not naming names, giving everyone a bad rap in the process.

Read the full Wall Street Journal article here.