With SpaceX, OpenAI, and Anthropic, we're likely to see 3 of the largest IPOs ever (by a wide margin) this year. Will existing institutional investors trim other positions to allocate a lot of capital for these mega listings or is this not a concern?
At least all the index funds are obligated to, right?
Index funds all make active choices and often hold companies not in the original index. They are more passive than a traditional funds that buys and sells all the time, but they still make active choices. When an index changes stocks they can look up the price - but the funds mirroring the index need to make real trades that if not carefully done will change the value of the stocks (and cause the fund to under perform the index), so index funds have plans to prevent this. Compared to a traditional fund an index fund looks passive and there is much much less for the manager to do - but that doesn't mean the managers do nothing.