RE: Mid Cap25 Feb 2025 23:17
It depends on what the rules for each fund are and how the fund managers approach the task. Some may have already been buying in anticipation if they can. Some may have to wait for official confirmation of the changes next Wednesday, some perhaps even wait until the changes are made on 24th March to finalise their position. The exiting companies they have to sell to fund the new entries are still part of the 250 until then so likely to be a phased approach in most cases.
But the fund analysts weren’t waiting around for today’s press release which is already two days out of date. They would already know/forecast what the changes are likely to be a long way out. Prices then often fall into the rebalance date to accommodate final buy orders, and some off-book movements between funds within the same management stable are likely as well.
Many tracker funds don’t hold an exact weighting of each index constituent. Their objective is generally to match, or exceed, the overall index and there are various ways of achieving that. Some are really passive and only hold a sample size of the individual stocks, making up the rest through proxies like maybe buying the sector index, or in this case the underlying commodity that our SP has a correlation to? Many funds have their own balancing/benchmarking dates to consider as well.
I'm obviously generalising a lot above but it's never as straight forward as just 'the trackers will have to buy'.
Total value of all FTSE 250 companies at close yesterday - £305,885m, total MCap of ATYM - £525.74m = just 0.17% weighting of total tracker values, lower once you adjust for the proxies etc.
Of more relevance to the SP here is the surge in Cu after close tonight…