The alleged Mt. Gox insolvency document claims that they lost about 744,408 BTC due to malleability-related theft which went unnoticed for several years. This is an address that just happens to have had 782,558 BTC flow through it over the last two years.

Of course, if the Mt. Gox document is a fake, the author could easily have chosen an amount that corresponded to an address that had such a number of Bitcoins flow through it.

It's difficult to know what's going on here.

The account shows transactions roughly matching the number of BTC missing from Mt. Gox. The recent transaction lots are large: 3000 - 15,000 BTC going back to December (at least, I'm still looking). That's $1.5 - $7.5 million in daily TX, which is pretty damned significant. Well above financial reporting requirements pretty much anywhere. For a long time this was at $10k in the US, though that threshold is now lower with improved technical capabilities.

Odd story: a friend of mine was a bagman for a con artist who happened to get caught. The friend ended up testifying in the case. Quite some years back.

Edit: The account dates to April, 2012, with lots of TX, including large blocks, even fairly early on. There's some discussion at reddit here:

http://www.reddit.com/r/Bitcoin/comments/1yvdcd/heres_a_summ...

MtGox is the context i believe