Earlier quoted context omitted.
I believe your understanding if the situation is flawed, if you are a US citizen. The $3000 per year applies to capital losses. You did not suffer a capital loss. You suffered a loss due to bank insolvency. If you realized your gains in 2013, you actually owe taxes on $500,000 for your 2013 taxes, which is roughly $250k. I believe your losses due to bank insolvency will apply to your income for 2014. But you may be o…
Lets see if I understand this (I am not in the US) - the bitcoins count as an asset, you sell these bitcoins for dollars at MtGox and at this point the tax is due regardless of whether you actually get the dollars out of MtGox? So any time between you selling bitcoins and actually getting the cleared funds out of an exchange leaves you with the risk of a fairly serious tax liability if the exchange can't actually giv…
During the dotcom boom, many, many people faced tremendous tax liabilities because of ill-timed tax strategies. For example, they had stock options that were worth millions, but instead of selling them, they exercised them in order to hold them to get long term capital gains. So for example, they had options worth $10M, and they exercised them. They faced an immediate tax liability for $10M, but then the dotcom bust hit, and they lost all $10M, leaving them with $10M in taxes but nothing to pay it back with. I personally knew several coworkers that suffered this.
I believe it was only recently, over 10 years after the fact, that the IRS changed how they treated this so that people didn't go bankrupt from this.