| You're being intentionally obtuse, for what, internet points? > kgwgk: But you can trade at the closing price, which is the one used by S&P to do their numbers, can't you? > readams: No you can't. You can only buy a stock based on the set of offers to sell that stock readams is unequivocally correct here. You can attempt to trade at the closing price, but doing so is entirely at the mercy of whether or not enough open offers exist to sell that stock. > chollida1: Then you said the closing price wasn't special. This as well was shown to be false as many ETF's are marked by the closing prices of certain markets, notably the NYSE. This point by readams is also true. The closing price of a stock isn't special — it's, as (s)he said, simply the price of the last trade of the day. The fact that some ETFs are marked by the price of market close makes their trading price "special", but that doesn't imply anything particular about the closing price of the asset(s) they're based on. > chollida1: Then you said you aren't guaranteed to get the closing price. This was an even stranger error as the message before I showed you the MOC order which indicates that you will trade at the closing price. Again, readams is correct. You're guaranteed to get the closing price if and only if there are open orders at that price. Which is a big if and only if, and not actually a guarantee. > chollida1: Finally you tripled down on this mistake by changing your argument that technically there might not be any trading partner at the close. This is technically true that in theory it might happen, but in practice I'll sit and wait for you to find me a case where this happened. Consider the context of this entire conversation: index funds that manage billions in assets. If you don't think they can utterly exhaust open buy/sell orders at market close for any trade they need to execute to track their index, you've lost your mind. This whole thread was about how these funds have to strategically place their orders to track the underlying index as faithfully as possible, without losing their shirts to vultures who know that large funds have to execute certain orders to stay on track. |
The closing price is special -- there's a special procedure to set the price and determine which orders execute (quite similar to the opening procedure), NYSE has a closing auction, NASDAQ has a closing cross, I'm sure most other exchanges have similar.
If there's no market/limit on close orders for a given stock, then the closing price would be the last trade; presumably the same for a stock which had its trading halted earlier in the day.