SHANGHAI, April 10 (Reuters) -Chinese regulators have fined Alibaba 18 billion yuan ($2.75 billion) - around 4% of its revenues in 2019 - for violating anti-monopoly rules and abusing its dominant market position.

The State Administration for Market Regulation (SAMR) said that after an investigation launched in December, it had determined that Alibaba Group had been “abusing market dominance” since 2015 by preventing its merchants from using other online e-commerce platforms.

It said the practice violates China’s anti-monopoly law by hindering the free circulation of goods and infringing on the business interests of merchants.

The SAMR ordered Alibaba to make “thorough rectifications” to strengthen internal compliance and protect consumer rights.

The company said in a statement posted on its official Weibo account that it “accepted” the decision and would resolutely implement SAMR’s rulings. It said it would also work to improve corporate compliance.

The practice of preventing merchants from listing on rival platforms is a long-standing one. The market regulator spelled out in rules issued on February that it was illegal.

Alibaba has also been under heavy scrutiny since its founder Jack Ma criticised China’s regulatory system in October.

Ant Group, Alibaba’s fintech arm, also saw its $37 billion listing plans dramatically suspended by authorities in November.