We take dollars

San Francisco start-up Coinbase has completed a second round of funding of $5m for future development of its Bitcoin wallet and exchange platform.

The investment was led by Union Square Ventures and will be spent on hiring more staff and covering operating costs.

Company founders Fred Ehrsam and Brian Armstrong - a Goldman Sachs trader and former developer at Airbnb - told the Wall Street Journal, "We need ten people yesterday."

The company was turning over $1m a month in February, but exchanged $15m of dollars into bitcoins, or vice versa, at one per cent commission, in April. It claims 121,000 users and 300 merchants including dating site OKCupid.

It provides exchange services as well as offering online wallets for consumers and merchant services for websites or traditional businesses, which wish to take bitcoins.

Coinbase

said turnover had been constrained by it hitting maximum buys per day - sometimes within hours of opening. It hopes to improve this situation with fixes soon.

It was developed last summer at technology incubator Y Combinator which provided seed funding for Reddit, Scribd and Airbnb amongst others. Coinbase got $600,000 of seed funding in December 2012.