blockchain.info marks the sending address as BTC Guild. AMs account (67117) on BTCGuild is still sitting around the same hashrate it's been at for the last month or so (270,868.32 GH/s). Just a little confused on what might be happening here.
The very exact value of 10 BTC each time also suggests it's not just mining income, which would vary by at least a small fraction of a bitcoin from payout to payout.