Hello World,
Macroeconomics
Professor Buddha
It is possible to steal bitcoins; theft has been documented on numerous occasions. At other times, Bitcoin exchanges have shut down, taking their clients' bitcoins with them. A Wired study showed that 45 percent of Bitcoin exchanges end up closing.[103]

On 19 June 2011, a security breach of the Mt. Gox Bitcoin exchange caused the nominal price of a bitcoin to fraudulently drop to one cent on the Mt. Gox exchange, after a hacker allegedly used credentials from a Mt. Gox auditor's compromised computer illegally to transfer a large number of bitcoins to himself. They used the exchange's software to sell them all nominally, creating a massive "ask" order at any price. Within minutes the price reverted to its correct user-traded value.[104][105][106][107][108][109] Accounts with the equivalent of more than US$8,750,000 were affected.[106]

In July 2011, the operator of Bitomat, the third largest Bitcoin exchange, announced that he lost access to his wallet.dat file with about 17,000 bitcoins (roughly equivalent to US$220,000 at that time). He announced that he would sell the service for the missing amount, aiming to use funds from the sale to refund his customers.[110]

In August 2011, MyBitcoin, a now defunct Bitcoin transaction processor, declared that it was hacked, which caused it to be shut down, paying 49% on customer deposits, leaving more than 78,000 bitcoins (equivalent to roughly US$800,000 at that time) unaccounted for.[111][112]

In early August 2012, a lawsuit was filed in San Francisco court against Bitcoinica — a Bitcoin trading venue — claiming about US$460,000 from the company. Bitcoinica was hacked twice in 2012, which led to allegations that the venue neglected the safety of customers' money and cheated them out of withdrawal requests.[113][114]

In late August 2012, an operation titled Bitcoin Savings and Trust was shut down by the owner, allegedly leaving around US$5.6 million in Bitcoin-based debts; this led to allegations that the operation was a Ponzi scheme.[115][116][117][118] In September 2012, the U.S. Securities and Exchange Commission had reportedly started an investigation on the case.[119]

In September 2012, Bitfloor, a Bitcoin exchange, also reported being hacked, with 24,000 bitcoins (worth about US$250,000) stolen. As a result, Bitfloor suspended operations.[120][121] The same month, Bitfloor resumed operations; its founder said that he reported the theft to FBI, and that he