I imagine that all the managed funds that track the ASX index...

I imagine that all the managed funds that track the ASX index will be into buying mode once the index rebalance is announced, but they'll progressively increase their holdings over a few weeks rather than just a few days. They won't want to drive their entry price up too high but they'll be sitting there to soak up any and all sellers, until they've accumulated enough stock to bring their NEU holdings into proportion to the size of their funds invested in the ASX. I imagine they'll try to avoid putting too much of a spike in our share price. But $72m worth of stock are a lot of shares to be bought, and if there aren't that many sellers emerging at the trading range of current prices then there'll inevitably be a rise in the share price to release that many shares from likely sellers.