Mt. Gox, called "Mount Gox" or simply "Gox", was the most widely used bitcoin currency exchange market from shortly after its inception in 2010 to its insolvency late 2013. The market was closed February 25, 2014 and has since filed for bankruptcy protection in Japan and the United States, after losing 640 thousand bitcoins.
A registrant on Mt. Gox had at least two sub-accounts: one for bitcoins (BTC), and one for fiat currency. Bitcoins were bought using funds from the trader's fiat account, and the proceeds from the sale of bitcoins were deposited into the same account. Trading always involved bitcoins as trading between different national currencies was not offered.
Trades on Mt. Gox's executed from balances on deposit with the exchange which in turn made trading on the market instantaneous, compared to most other Bitcoin markets of 2010 where a subsequent settlement occurred manually between the trading partners. The disadvantage of this was that a third party had to be trusted with keeping the money safe.
Buying and selling
A buy order was executed partially or in full when the price bid could be matched against a sell order that was at or below the bid amount. A sell order was executed partially or in full when the price asked could be matched against a buy order that was at or above the ask amount. Orders that could not be matched immediately remain in the orderbook.
Unfunded orders did not appear in the order book, but were automatically inserted when a deposit was credited. For example, Mt. Gox allowed the entry of a "buy" order even if the account had insufficient funds. If possible, Mt. Gox would execute a portion of the order if it could be partially funded. If a deposit was later credited and the deposit resolves the insufficient funds status of an outstanding order, the order would be immediately activated, and if possible, executed.
Mt. Gox charged a trading fee of up to 0.6% from each party of successful trades made through the market. The fee appeared in the account history next to each trade. The trading fee was discounted for larger customers based on volume, which was calculated as a sliding window over the last 720 hours (30 days).
The fees were, by default, subtracted from the proceeds of each trade (e.g., a buy of 1.0 BTC will add to the account balance 0.994 BTC when the exchange fee is 0.6%). An account setting would allow fees to be added to the purchase amount instead (e.g., buying 1.0 BTC at $5 will cost about $5.03 when the exchange fee is 0.6%).
The exchange went online on July 18, 2010.
On October 10, 2010 the exchange switched from PayPal to Liberty Reserve as the main funding option as a result of chargeback fraud. Former PayPal customers still had the possibility to withdraw their USD using alternative methods.
Announced on March 6, 2012 was the Merchant Solution and API
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 fabricate a large number of bitcoins for himself. He used the exchange's software to sell them all nominally, creating a massive "ask" order at any price. The price eventually corrected to its correct user-traded value. Accounts with the equivalent of more than $8,750,000 were affected. In order to prove that Mt.Gox still had control of the coins, the move of 424,242 bitcoins from "cold storage" to a Mt.Gox address was announced beforehand and executed in Block 132749. It was later revealed that the coins may have never been in cold storage, as the proof-of-solvency transaction was broadcast through a remote Linux desktop and a single hot wallet.
In October 2011, about two dozen transactions appeared in the block chain (Block 150951) that sent a total of 2,609 BTC to invalid scripts. As they were impossible to satisfy/redeem, these Bitcoins were effectively destroyed.
On 22 February 2013, following an introduction of new anti-money laundering requirements by Dwolla, some Dwolla accounts became temporarily restricted. As a result, transactions from Mt. Gox to those accounts were cancelled by Dwolla. The funds never made it back to Mt. Gox accounts. Mt. Gox help desk issued the following comment: "Please be advised that you are actually not allowed to cancel any withdrawals received from Mt. Gox as we have never had this case before and we are working with Dwolla to locate your returned funds." The funds were finally returned on May 3, more than 3 months later, with a note "Please be advised never to cancel any Dwolla withdrawals from us again".
In March 2013, the new 0.8.0 version of Bitcoin Core temporarily forked off the main blockchain using differing rules on how transactions could be accepted. The Mt. Gox bitcoin exchange briefly halted bitcoin deposits. Bitcoin prices briefly dipped by 23% to $37 as the event occurred before recovering to their previous level in the following hours, a price of approximately $48.
Suspension of trading 2013
Mt. Gox suspended trading on 11 April 2013 until 12 April 2013 2 am UTC for a "market cooldown". The value of a single bitcoin fell to a low of $55.59 after the resumption of trading before stabilizing above $100. Around mid May 2013, Mt. Gox traded 150,000 bitcoins per day per Bitcoin Charts.
Mt. Gox suspended withdrawals in US dollars on June 20, 2013. The Mizuho Bank branch in Tokyo that handled Mt. Gox transactions pressured Mt. Gox from then on to close its account. On July 4, 2013, Mt. Gox announced that it had "fully resumed" withdrawals, but as of September 5, 2013, few US dollar withdrawals had been successfully completed.
On August 5, 2013, Mt. Gox announced that they incurred "significant losses" due to crediting deposits which had not fully cleared and that new deposits would no longer be credited until the funds transfer was fully completed.
CoinLab lawsuit and Homeland Security seizure of US funds
On 2 May 2013 CoinLab filed a $75 million lawsuit against Mt. Gox alleging a breach of contract. The companies had formed a partnership in February 2013 under which CoinLab handled all of Mt. Gox's North American services. CoinLab's lawsuit contends that Mt. Gox failed to allow them to move existing U.S. and Canadian customers from Mt. Gox to CoinLab.
On 15 May 2013 the US Department of Homeland Security (DHS) issued a warrant to seize money from Mt. Gox's US subsidiary's account with payment processor Dwolla. The warrant suggests the US Immigration and Customs Enforcement, an investigative branch of the DHS, felt that the subsidiary, which was not licensed by the US Financial Crimes Enforcement Network (FinCEN), was operating as an unregistered money transmitter in the US. Between May and July more than $5 million were seized.  On 29 June 2013, Mt. Gox received its money services business (MSB) license from FinCEN.
Withdrawals delayed or refused
Wired Magazine reported in November 2013 that customers were experiencing delays of weeks to months in withdrawing funds from their accounts. The article said that the company had “effectively been frozen out of the U.S. banking system because of its regulatory problems”. Customer complaints about long delays were mounting as of February 2014, with more than 3300 posts in a thread about the topic on the BitcoinTalk online forum.
Bankruptcy and shutdown
- Main article: Collapse of Mt. Gox
- 2011-06-07 on #bitcoin-otc: "MagicalTux: you could use the count of users on mtgox (went over 30k recently)"
- MtGox announcement on forum
- Mtgox is changing owners
- World's Leading Bitcoin Exchange, Mt.Gox, acquires MtGoxLive.com
- Mt.Gox launches the definitive bitcoin checkout solution
- Huge Bitcoin sell off due to a compromised account - rollback
- Script error: No such module "citation/CS1".
- Script error: No such module "Citation/CS1".
- Mick, Jason (19 June 2011). "Inside the Mega-Hack of Bitcoin: the Full Story". DailyTech. http://www.dailytech.com/Inside+the+MegaHack+of+Bitcoin+the+Full+Story/article21942.htm.
- Lee, Timothy B. (19 June 2011). "Bitcoin prices plummet on hacked exchange". Ars Technica (Condé Nast). http://arstechnica.com/tech-policy/news/2011/06/bitcoin-price-plummets-on-compromised-exchange.ars.
- Mark Karpeles, 20 June 2011, Huge Bitcoin sell off due to a compromised account – rollback, Mt. Gox Support
- Chirgwin, Richard (19 June 2011). "Bitcoin collapses on malicious trade – Mt Gox scrambling to raise the Titanic". The Register. http://www.theregister.co.uk/2011/06/19/bitcoin_values_collapse_again/.
- Block 132749. Main chain. 2011-06-23. Hash 00000000000004bea72d0f390194b08162665a4fc99469c576338cd37164a15a. Block explorer
- /r/Bitcoin thread 3fe92x. I'm Ashley Barr, A.K.A "Adam Turner", the first Mt.Gox employee, and alleged DPR (:/). AMA 1 August 2015. This post
- Lee, Timothy. "Major glitch in Bitcoin network sparks sell-off; price temporarily falls 23%". Ars Technica (Condé Nast). http://arstechnica.com/business/2013/03/major-glitch-in-bitcoin-network-sparks-sell-off-price-temporarily-falls-23/. Retrieved 12 March 2013.
- Blagdon, Jeff. "Technical problems cause Bitcoin to plummet from record high, Mt. Gox suspends deposits". The Verge. http://www.theverge.com/2013/3/12/4092898/technical-problems-cause-bitcoin-to-plummet-from-record-high. Retrieved 12 March 2013.
- "Bitcoin Charts". Bitcoin Charts. http://bitcoincharts.com/charts/mtgoxUSD#rg60zczsg2013-03-12zeg2013-03-15ztgSzm1g10zm2g25zv.
- "Twitter / MtGox: Trading is suspended until". Twitter.com. https://twitter.com/MtGox/status/322355614414147588. Retrieved 2014-02-17.[dead link]
- Cite error: Invalid
<ref>tag; no text was provided for refs named
- McMillan, Robert (20 June 2013). "Bitcoin’s Big Bank Problem: Why Did Mt. Gox Halt U.S. Payouts?". Wired (Condé Nast). http://www.wired.com/wiredenterprise/2013/06/mt-gox-stops/.
- Vigna, Paul (5 July 2013). "Bitcoin operator Mt. Gox resumes withdrawals". The Wall Street Journal. http://blogs.wsj.com/moneybeat/2013/07/05/bitcoin-operator-mt-gox-resumes-withdrawals/.
- Vigna, Paul (31 July 2013). "Bitcoin exchange Mt. Gox still grappling with slowdown". The Wall Street Journal. http://blogs.wsj.com/moneybeat/2013/07/30/bitcoin-exchange-mt-gox-still-grappling-with-slowdown/.
- Marron, Donald (3 September 2013). "How Bitcoin spreads violate a fundamental economic law". Forbes. http://www.forbes.com/sites/beltway/2013/09/03/how-bitcoin-spreads-violate-a-fundamental-economic-law/.
- Script error: No such module "citation/CS1".
- Chen, Adrian (2 May 2013). "Massive Bitcoin Business Partnership Devolves Into $75 Million Lawsuit". Gawker Media. http://gawker.com/massive-bitcoin-business-partnership-devolves-into-75-487857656. Retrieved 8 June 2013.
- Dillet, Romain (16 May 2013). "Feds Seize Assets From Mt. Gox’s Dwolla Account, Accuse It Of Violating Money Transfer Regulations". TechCrunch (AOL Inc.). http://techcrunch.com/2013/05/16/mt-gox-dwolla-account-money-seizure/. Retrieved 10 February 2014.
- Buterin, Vitalik (29 June 2013). "MtGox Gets FinCEN MSB License". Bitcoin Magazine (Coin Publishing Ltd.). http://bitcoinmagazine.com/5560/mtgox-gets-fincen-msb-license/. Retrieved 10 February 2014.
- McMillan, Robert; Metz, Cade (6 November 2013). "The rise and fall of the world's largest Bitcoin exchange". Wired (Condé Nast). http://www.wired.com/wiredenterprise/2013/11/mtgox/. Retrieved 8 February 2014.
- Wong, Joon Ian (4 February 2014). "Poll: Are you having Mt. Gox withdrawal issues?". CoinDesk. http://www.coindesk.com/poll-mt-gox-withdrawal-issues/. Retrieved 9 February 2014.