Some Morgan stanley trader entered a wrong order of 5400 index futures contracts (they are supposed to buy only 54) towards the market close. This triggered a jam in the exchange n some arbitrage programme trading, as well as some variance swap players which were supposed to close their position on MOC orders (which is not cancellablle after 1540) to cover up buying index. some trader estimated the total amount of buying created by this error trade to be around 5bln usd.