alt Hacker NewsI've heard of the changes to the NASDAQ rules and I somewhat get how they make it so these stocks are included in index funds earlier than before. As far as I know, NYSE and others haven't done the same change so index funds there are "safe", i.e. will include the stocks only after a longer period, implying that it will have settled in value by then. Is that true at all? I'm sure the situation is much more complicated, but I do wonder how to figure out how much I'm affected.
There is a huge amount of misinformation on this topic, including in this thread, at the minute.
Some index funds have a very long horizon before they include them (e.g. a year). Others are "fast-tracked" (e.g. notably VTI). Most of those, however, are float-adjusted, so only the stock available for trade is considered part of the marketcap. So e.g. VTI / VTSAX will buy spacex relatively quickly after the IPO but at the float-adjusted weight of ~$75B because that's the % of stock available.
If you care alot about this, now is the time to understand how your index fund treats IPOs wrt to delays + float adjustment.