Bitcoin exchanges Bitstamp and BTC-e are currently handling about 75% of total trades in the popular digital currency, following the collapse of MtGox.
Bitstamp now handles more than 44% of total bitcoin trading volume, while BTC-e manages about a 30% share, according to Bitcoin Average.
They are closely followed by Bitfinex at 22.83%, while itBit handles a 2.37% trading volume.
Small players such as LocalBitcoins, CampBx and Justcoin are representing trade volumes less than 1%.
About 70% of all bitcoin transactions are done in US dollars, followed by the Chinese yuan at 16%, the Hong Kong dollar at 5.7% and the euro at 4.7%.
Trading volumes in Bistamp and BTC-e began to rise as MtGox's problems mounted. The three exchanges accounted for about 30% each of total trading done in US dollars at the end of 2013.
Japan's MtGox, which had hosted 80% of the world's bitcoin trades, collapsed after losing about 850,000 bitcoins to DDoS attacks. The company has filed for bankruptcy protection in Japan on 28 February.
The company noted that its liabilities totalled 6.5bn yen ($64m, £38m, €46.5m), while it has only 3.8bn yen of assets.
Bitcoin is currently trading at $617.24, according to CoinDesk Bitcoin Price Index.