Polymarket has seen remarkable activity in its election markets for Ethiopia and Romania, amassing over $600 million in combined trading volume.

A significant amount of this trading involved contracts related to candidates deemed unlikely to win. In the recent federal election in Ethiopia, Prime Minister Abiy Ahmed’s Prosperity Party captured 438 seats in the parliament, while the closest rival managed just 10. Interestingly, the trading volume on contracts predicting Ahmed’s victory was limited to $173,000.

In contrast, contracts suggesting that his chief of staff, Shimelis Abdisa, would become the next leader attracted more than $41 million, with total trading in this market exceeding $285 million.

Chris Park, a former Polymarket trader who now leads MSR Decode, reported that nearly $284 million of the volume stemmed from accounts trading contracts back and forth among themselves. Barnard College economics professor Rajiv Sethi referred to this behavior as a form of trading-volume manipulation.

Polymarket had established that the Ethiopia market would be settled in October following the prime minister’s official appointment and swearing-in. However, over the 123 days post-election, there were a series of unusual transactions on the platform. Shana Bautista, a representative from Polymarket, shared with WIRED that the team detected and investigated this suspicious activity and took action by blocking the involved accounts.