Massive Transactions?

[the joint]

So, looking at www.bitcoinmonitor.com it appears as though some very high volume transactions have been taking place in the past few hours.  Some transactions are between 5,000 and 10,000 Bitcoins, but these aren't trades on exchanges.  What are all these high volume transactions?  Is this what activity on the Bitcoin black market looks like?

[Revalin]

Here's an example: https://blockexplorer.com/tx/e9db67d0018769521d6773345180731dab1f1c4905e4f5bd9cb5a91a3da87202

That's just someone with 4050 BTC who sent 153.5 BTC to someone and got 3896.5 BTC of change back.  These are frequently pools paying out from their fairly large central wallets, but it could be anyone with 4kBTC who wanted to pay someone 150BTC.

[RyNinDaCleM]

Or, sending to GOX!

[sadpandatech]

  Or Bitcoinica cashing out everyones BTC to cover their users' spreads.