I am having big problems believing GOX lost 800.000 bitcoins in a couple of years because of the transaction malleability issue.
What if Gox , while it was growing in size, just like the banks decided: "We do not need to hold 100 percent of customer bitcoin in reserve, because at no time will all the customers withdraw all their bitcoin from Gox. "
and then instead of lending out customers bitcoins to others, for interest, Gox decided to simply sell a percentage of the customer bitcoin they held in reserve huh ?
They could not lend out coins they had in reserve because the public would then immediately realize Mt. Gox was fractional reserve banking bitcoin, but if they just sold them on gox themselves pretending it was customers selling them, nobody could find out.
If Gox did this then they were fractional reserve banking bitcoin, diluting the amount of coins (IOU's from Gox) poeple believe they have, and have been driving down the price of bitcoin.
Gox is (was) so incompetent that fraud doesn't even have to have occurred for me to believe they lost all of the bitcoins.
For what it is worth, I think someone at Gox, or who had physical access to Gox's computers, took the bitcoins (which would be criminal), or that their security was so lax that their cold wallet was not cold and not secure (which would be negligent).
I don't know what happened. But I know what didn't happen. It was not malleability. Malleability would have required two very unlikely things:
#1: Gox losing more than 500 bitcoins a day, every day, from the day they opened until the day they went dark, without noticing. This seems impossible.
#2: Gox customer service honoring requests to re-send lots of large withdrawals over and over again. Even the dimmest customer service agent would get suspicious if someone called every day for three years to say his 500 bitcoins (which would have exceeded the daily withdrawal limit in the first place) had still not arrived.