Anatomy of A High Frequency Algorithm Attack on Gold - Dimitri Speck

We can clearly see the up and down of the prices [within less than a second]. Neither a mistrade, nor a move in the spot market, nor a building up of several high frequency programs (like in the flash crash of the stock market on 6 May, 2010) can cause such swings... the spot market can't be the cause in question, as it lagged behind the sharp drop. Instead it was a phenomenon of the futures market. Generally, no person but only a high frequency computer program can act so fast. Due to the lack of any suitable alternative, its purpose must have been price manipulation. Indeed it was achieved: the price stayed more than $20 lower for hours -- time enough to get back the costs of the operation.