some investment funds invest based on the asx all ords. ihl was...

some investment funds invest based on the asx all ords. ihl was recently added and therefore these funds must rebalance their portfolios prior to the index rebalance day. so they exit stocks en mass and also enter. it typically doesnt have a huge effect on the sp as brokers would be buying pre fund buying to unload into the rebalance buying. pretty good chance this also explains the recent plummet in the sp. the closing auction action today wont really have a material sp impact moving forqard other than the fact that those shares wont be traded while ihl is in the all ords. if we drop out or move into the 300 expect some similar action around those rebalance times