A Chinese Bitcoin exchange that held up to $4.1 million in users' accounts has gone offline and everyone involved with it has vanished, according to CoinDesk.

The GBL exchange claimed to be based in Hong Kong but turns out to have been headquartered in China. The Hong Kong Standard reports:

The company appears to have launched in May 2013, with its domain btc-glb.com registered on 9th May and a post later that month by Bitcoin Talk forum user zhaoxianpeng promoting the site.

Some mainlanders went to the IFC office listed on its website, but this turned out to be a false address.

Fourteen of them made a report to the Hong Kong police.

WantChinaTimes notes that GBL had not obtained any of the usual business licenses required to operate a financial services company. Bitcoin banks and exchanges have a habit of disappearing, the WCT says:

Research conducted by Southern Methodist University assistant professor Tyler Moore and Carnegie Mellon University assistant professor Nicolas Christin found that 18 of the 40 Bitcoin trading platforms set up in the past three years had closed, including TradeHill, which was once the second largest in terms of transaction volume.

Moreover, 13 of the discontinued services closed without any prior notice, while the remaining five were forced to shut down following hacker attacks. Only six of them were known to have offered refunds to users.

Business Insider noted just a few days ago that an Australian Bitcoin bank, "Tradefortress," closed with $1 million in Bitcoin funds missing. The bank turned out to be operated by an 18-year-old boy who lived in a block of apartments in Hornsby, a suburb of Sydney.