The German Federal Cartel Office has imposed a total fine of €90.5m on several retailers, as part of an investigation on fixing beer prices. The probe began in 2010.

During the investigation, the cartel office found that retailers collaborated with the German unit of Anheuser-Busch InBev NV between 2006 and 2009 to fix the prices of beer, reported the Wall Street Journal.

The retailers colluded with the brewer of Hasseröder and Beck’s beer brands.

“The retailers colluded with the brewer of Hasseröder and Beck’s beer brands.”

Retailers who were involved in the price-fixing scandal include the EDEKA supermarket chain, Metro, NETTO Marken-Discount, and A Kempf Getränkegroßhandel.

Fines for these firms were reduced once they reached a settlement.

AB InBev and supermarket group REWE did not have fines imposed on them as they cooperated in the probe.

This news comes as Germany’s beer industry is currently celebrating the 500th anniversary of Reinheitsgebot, a beer purity law, decreed in Bavaria by Duke Wilhelm IV in 1516.

According to Reinheitsgebot, water, malt, hops and yeast should only serve as ingredients in the brewing process. In 1906 this law became mandatory for all German beer manufacturers.