portfolios and rebalancing, page-2

Yes spot on... it also means that after the announcement of commercialisation there may be an opportunity to still buy TIS cheap as the fund will need to sell as it goes up. The fund won't be selling on fundamentals, but on their portfolio rules, so will be effectively giving away money.

So, hypothetically the fund manager may need to sell at the start of this month to re-balance. If they expect big news this month that would be very frustrating, so you might put your whole months order into the market at once in the hope it scares people off. If an announcement comes out you'll end up selling at the open price which may be much higher. All hypothetical of course, but that's the best explanation I can come up with for the odd behaviour.