I don't think MtGox has confirmed any losses, nor would I expect them to. But consider both the way they've spoken about the issue (https://www.mtgox.com/press_

I don't think MtGox has confirmed any losses, nor would I expect them to. But consider both the way they've spoken about the issue (https://www.mtgox.com/press_release_20140210.html https://www.mtgox.com/press_release_20140210.html)... "In the meantime, exchanges and wallet services - and any service sending coins directly to third parties - should be extremely careful with anyone claiming their transaction did not go through." ...and nullc's speculation just before the latest blamestorming (http://www.reddit.com/r/Bitcoin/comments/1x93tf/some_irc_chatter_about_what_is_going_on_at_mtgox/cf99yac http://www.reddit.com/r/Bitcoin/comments/1x93tf/some_irc_cha...)... "Worse, some of this may have resulted in users getting paid multiple times and could have been intentionally triggered with that end in mind if someone helpfully fixed some transactions and then noticed they got paid twice. (I think this is unlikely to have caused large losses, before people run off worrying about that, both because of the reuse of the oldest inputs and because of the hot wallet/cold wallet split)." Thus I find it reasonable to surmise, based on MtGox's own description of the risk, that MtGox has in some cases issued unnecessary redundant payments to customers complaining that "it's been days and the TXID you reported still hasn't shown up!" An earlier MtGox issue nullc also mentions – using too-young coins – could similarly have resulted in double-payments. (MtGox issues a transaction that can't confirm; customer complains and gets 2nd transaction issued that confirms; first transaction later confirms when coins have aged enough.) If so, that perhaps helped train MtGox customers, even if not MtGox itself, for the redundant-payment potential from malleability.