Reaching for yield (and prospectively capital appreciation) while shortening duration had become the new 'smart money' trade as we saw HY credit curves steepen earlier in the year (only to become the pain-trade very quickly). The attraction of those incredible yields on short-dated sovereigns was an obvious place for momentum monkeys to chase and it seems that was the undoing of MF Global. The Dec 2012 Italian bonds (of which MF held 91% of its ITA exposure in), as highlighted in today's Bloomberg Chart-of-the-day, appears to be the capital-sucking instrument of doom for the now-stricken MF.
As if we need to remind readers, there is a reason why yields are high - there is no free lunch - and while some have already leaped to the defense of the bet-on-black Corzine risk management process with comments such as 'He was simply early and will be proved correct' should remember that only the central banks have bottomless non-mark-to-market pockets to withstand the vol.
Perhaps the largest lesson, and one that Mr. Barroso, Van-Rompuy, Draghi et al. should bear in mind is just how quickly a levered (firm not instrument) position supporting risky sovereign debt can go against you - but then today's EFSF issue demand perhaps makes that discussion moot.