BENGALURU (REUTERS) - Coinbase Global reported a larger-than-expected quarterly loss as investors worried by this year's rout in risky assets shied away from trading in cryptocurrencies, sending its shares down 6 per cent after the bell on Tuesday (Aug 10).

Trading volumes at the cryptocurrency exchange more than halved to US$217 billion (S$299 billion) in the second quarter, with retail participation sinking 68 per cent and institutional trading falling 46 per cent.

Coinbase said it expects trading volumes to fall further in the current quarter, underscoring the turmoil brought to the sector by the collapse of certain crypto ventures and a broader sell-off in financial markets.

That downturn has sent bellwether bitcoin 50 per cent lower in 2022, forced several companies including Coinbase to cut jobs and raised fears of a drop in interest from small traders.

Coinbase said its monthly transacting users fell 2 per cent sequentially to 9 million in the April-June quarter.

"Coinbase did not see a mass migration off its platform during the quarter, but its users are becoming more passive in their cryptocurrency investing," said Mr Michael Miller, equity analyst at Morningstar Research.

That could be a material drag on Coinbase's earnings as the firm generates most of its revenue from trading fees, Mr Miller added.

Adjusted loss was US$4.76 a share in the quarter, compared with the US$2.65 expected by analysts, according to Refinitiv data. Revenue fell 63 per cent, missing market expectations.

Even though operating expenses surged 37 per cent, the firm lowered its annual expenses forecast for technology, development and administration to between US$4 billion and US$4.25 billion, from US$4.25 billion to US$5.25 billion.

"The reduction is unlikely to restore profitability at current revenue generation levels," Mr Miller said.