A spike bet is a kind of spread bet. In this case, the bets are placed on the price movement of an underlying asset. In this case, the FTSE index. It is important to note that the spiked price will benefit the trades in the opposite direction. Therefore, it is not practical for a spread betting firm to use this tactic. Nonetheless, it is worth noting that the CMC quotes are quite similar to those of other spread betting firms. It is difficult to see how this would be done without collusion among spread betting firms.