Polymarket was found to have a data bug that caused trading volume to be counted twice.

A researcher from Paradigm stated that the reported activity and trading volume of the prediction market platform Polymarket may be higher than reality due to a “data error.”

Storm, a researcher at Paradigm, said that most major dashboards have inadvertently double-counted Polymarket’s trading volume, unrelated to wash trading. The reason is that Polymarket’s on-chain data creates multiple OrderFilled events for the same transaction—one for the maker and one for the taker—but many dashboards add them up as two separate transactions.

This error causes both the nominal volume and the cash flow volume to be inflated. This could affect the reputation of Polymarket—a platform considered one of the few recent crypto success stories.

Diverse market volumes use different metrics. Source: ParadigmICE recently valued Polymarket at $9 billion, based on $25 billion in trading volume, a figure that may need to be reconsidered. Several major dashboards such as DefiLlama, Allium, Blockworks, and many dashboards on Dune are also believed to have double-counted data.