China's market regulator said on Wednesday it had fined e-commerce giant JD, Alibaba Group's business-to-customer platform Tmall and discount e-retailer Vip.com 500,000 yuan ($76,650) each for irregular pricing.

The State Administration for Market Regulation said in a release on its website that it had made the decision after it received consumer complaints over these companies' pricing strategies, such as raising the price first and then offering discounts, false promotion and inducing consumers to make transactions during the Nov 11 Singles Day online shopping carnival.

For instance, the price of instant noodles produced by Master Kong, or Kangshifu, was 12.5 yuan at Tmall after the platform launched a large-scale promotion campaign starting from Nov 14, but actually the price was unchanged compared with that on Nov 12 and Nov 13.

At JD, the price of Vinda toilet paper was 79.9 yuan after it offered discounts on Nov 3. However, the price was 77.9 yuan on Nov 2, lower than that during the promotional activities. In addition, an Apple laptop sold at Vip.com was 7,999 yuan. The e-commerce platform claimed "it is the lowest price among all e-retailers", but it could not provide supporting material to verify this claim.

Alibaba, JD and Vip.com were not available for comment when contacted. The move came after the authority launched an investigation last week into Alibaba for alleged monopolistic conduct, which refers to forcing merchants to sell on Alibaba's platforms exclusively and preventing them from selling on rival e-commerce websites.