We’ve discussed the peculiarities of the stock index futures’ expiration cycle in detail here before.
Commercial traders in the stock index futures behave quite differently than the Index traders or, small speculators who act as their counterparts. Collectively, this is perfectly logical. Index traders are positive feedback traders. Positive feedback traders add on to their bullish positions as the market climbs and scale out of their bullish positions as the market declines. This keeps their portfolio balanced to their available cash resources. This also places them on the side most likely to buy the highs and sell the lows. Typical trend following. Small speculators are a sentiment wild card. Their position is more price and sentiment based than anything else. The randomness of their sentiment makes their positions too yielding to lean on.