That depends on the value of the Bitcoins held in the MtGox account. If it was worth more than $10,000, which is very possible considering the meteoric rise of Bitcoins this year, you could have an FBAR reporting requirement.
A FBAR reporting requirement means that next year you would need to file a Form TD-F 90.22-1, electronically, by June 30th. The form itself is for the most part simple and self-explanatory.
As for the Coinbase coins, for the most part, "foreign" in "foreign currency" means issued by a foreign government. The government generally refers to Bitcoin and other digital currencies as "virtual" currencies.
EDIT: Followup. FATCA, the other foreign reporting requirement, only kicks in if the value of total foreign financial assets exceeds $50,000 at the end of the taxable year. If total foreign financial assets aren't worth $50,000 at the end of the year, FATCA shouldn't apply.
A FBAR reporting requirement means that next year you would need to file a Form TD-F 90.22-1, electronically, by June 30th. The form itself is for the most part simple and self-explanatory.
As for the Coinbase coins, for the most part, "foreign" in "foreign currency" means issued by a foreign government. The government generally refers to Bitcoin and other digital currencies as "virtual" currencies.
EDIT: Followup. FATCA, the other foreign reporting requirement, only kicks in if the value of total foreign financial assets exceeds $50,000 at the end of the taxable year. If total foreign financial assets aren't worth $50,000 at the end of the year, FATCA shouldn't apply.