NEW YORK (AFP) - Bitcoin on Thursday got a lift with the arrival of a new investment vehicle that lets wealthy and professional investors bet on the virtual currency.

SecondMarket, a New York-based investment platform that specialises in alternative ventures, began accepting investors in its Bitcoin Investment Trust, a private investment vehicle that will purchase the virtual currency, store it in a virtual safe of sorts and allot new shares of stock to shareholders as they buy in.

The fund kicked off with seed investment of US$2.25 million (S$2.82 million) from SecondMarket, which specialises in alternative investments. Mr Mark Murphy, a SecondMarket spokesman, said the fund had heard from financial professionals, technology figures, gold enthusiasts and others.

"There's really high interest," said Mr Murphy, who said there is no goal as far as the size of the fund. The fund's arrival comes as investors look for new ways to bet on the four-year old currency, increasingly used to make payments in online transactions.

There is an estimated US$1.5 billion in bitcoin on the market. Partisans of bitcoin say it offers promise as a global and easily transacted currency outside the purview of central bankers. SecondMarket designed the fund as a means for investors to bet on bitcoin without having to procure the currency themselves.

"We believe that bitcoin may have significant upside given the size and scope of the industries that are potentially impacted by bitcoin," said SecondMarket founder Barry Silbert in a statement. "However, bitcoin also faces regulatory uncertainty and widespread adoption issues that make investing in bitcoin a highly risky endeavour."

As a private fund, the venture is open to accredited investors, those who meet specific criteria such as, for an individual, earning at least US$200,000 a year for the last two years. The minimum investment in the fund is US$25,000.

The fund is regulated by the US Securities and Exchange Commission, but is not registered with the agency, Mr Murphy said. The fund's launch comes as some regulators have stepped up probes into use of the virtual currency.

The New York Department of Financial Services last month sent subpoenas to leading investors in bitcoin and expressed concern that it could be used by drug traffickers and gun runners and threaten US national security. The department said it was considering new regulations on the currency.