Can an ETF, open at a price other than what the pre-market was at?
If I understand you correctly, you are noticing that a stock's price can change drastically when the time changes from pre-market trading hours to open market hours. This could occur because a much smaller pool of investors make trades during pre-market and after-market hours. When the regular market opens there is a large influx of trades, causing the prices to jump. If you're talking about an ETF trading on Arca, it's probably because of the opening auction: The match price is the price that maximizes the volume that can be executed within the Auction Collars. The Core Open Auction will use the match price closest to the closing price of the previous trading day (based on normal market hours) if more than one indicative match price is valid. The core opening auction doesn't really take the opening session activity into account, as you can see - the market runs an auction and whatever price clears the most volume, within certain limits, is the opening print.
Not that I am aware. There are times that an option is available, but none have traded yet, and it takes a request to get a bid/ask, or you can make an offer and see if it's accepted. But the option chain itself has to be open. thanks.  I have real time quotes, but in the contest, if you put in a market order the trade might happen at the delayed quote price and not the real time price.  Does anyone know at which price it will trade, delayed or real time? "Your scenario depicts 2 ""in the money"" options, not ""at the money"". The former is when the share price is higher than the option strike, the second is when share price is right at strike. I agree this is a highly unlikely scenario, because everyone pricing options knows what everyone else in that stock is doing. Much about an option has everything to do with the remaining time to expiration. Depending on how much more the buyer believes the stock will go up before hitting the expiration date, that could make a big difference in which option they would buy. I agree with the others that if you're seeing this as ""real world"" then there must be something going on behind the scenes that someone else knows and you don't. I would tread with caution in such a situation and do my homework before making any move.   The other big factor that makes your question harder to answer more concisely is that you didn't tell us what the expiration dates on the options are. This makes a difference in how you evaluate them. We could probably be much more helpful to you if you could give us that information." "I think that any ETF is ""open source"" -- the company issues a prospectus and publishes the basket of stocks that make up the index. The stuff that is proprietary are trading strategies and securities or deriviatives that aren't traded on the open market. Swaps, venture funds, hedge funds and other, more ""exotic"" derivatives are the things that are closed. What do you mean by ""open source"" in this context?" It depends completely on the current order book for that security.  There is literally no telling how that buy order would move the price of a stock in general. I can't say I know everything about the underlying details, but from what I understand, your limit buy adds to the bid side of open orders, and one possibility is that someone placed a market order to sell when the bid price for the stock fell to $10 which was matched to your open limit order. So using your terminology, I would say the spot bid price is what fell to $10, even if for a brief moment. Whether or not it is possible for your order to be filled when the limit buy price is deeper than the current bid price is beyond me. It may have something to do with lot sizes. Not directly an answer to your question, but somewhat related: There are derivatives (whose English name I sadly don't know) that allow to profit from breaking through an upper or alternatively a lower barrier. If the trade range does not hit either barrier you lose. This kind of derivative is useful if you expect a strong movement in either direction, which typically occurs at high volume. "I assert that it's simply not possible for them to place an order that gets ahead of yours (the first step in ""sell it back to you at a higher price""). They only know your order was placed after it reaches the exchange and gets filled." "If you own a stake large enough to do that, you became regulated - under Section 13(d) of the 1934 Act and Regulation (in case of US stock) and you became regulated. Restricting you from ""shocking"" market. Another thing is that your broker will probably not allow you to execute order like that - directed MKT order for such volume. And market is deeper than anyone could measure - darkpools and HFTs passively waiting for opportunities like that." The best thing to do is not worry about what time is best to buy but put in a conditional order before the market opens. If your conditions are met during the trading day your order will go through and you will buy the shares. This keeps your emotions out of your trading and will stop you from either chasing the market or buying when you consider the wrong time. As you have already done your analysis and made your decision before market open, thus you should place your conditional orders and stop losses before market opens as well. "Firstly, if a stock costs $50 this second, the bid/ask would have to be 49/50.  If the bid/ask were 49/51, the stock would cost $51 this second.  What you're likely referring to is the last trade, not the cost.  The last trading price is history and doesn't apply to future transactions. To make it simple, let's define a simple order book.  Say there is a bid to buy 100 at $49, 200 at $48, 500 at $47.  If you place a market order to sell 100 shares, it should all get filled at $49.  If you had placed a market order to sell 200 shares instead, half should get filled at $49 and half at $48.  This is, of course, assuming no one else places an order before you get yours submitted.  If someone beats you to the 100 share lot, then your order could get filled at lower than what you thought you'd get.  If your internet connection is slow or there is a lot of latency in the data from the exchange, then things like this could happen.  Also, there are many ECNs in addition to the exchanges which may have different order books.  There are also trades which, for some reason, get delayed and show up later in the ""time and sales"" window. But to answer the question of why someone would want to sell low... the only reason I could think is they desire to drive the price down." Quoted from money.howstuffworks.com: NASDAQ has come up with an auction approach called the opening cross. Here's how it works. In the morning, a computer program looks at all the orders that have come in overnight in each different stock. Based on those orders, the program picks a price level that would be the best opening price. However, it also looks to see if there's a trade imbalance. For example, if a company announced bad news after the market closed, there might be 10 times more sell orders than buy orders. NASDAQ then broadcasts the price and imbalance information to its network of dealers with the goal of offsetting the imbalance. It then lets dealers place orders. This all happens very quickly, in a time window of two minutes or so, right before the market opens. Dealers can place orders, and those orders are factored into the opening price. Further reading here: Opening Price calculation Since the market is in general rather efficient, the price of the ETF will most of the time reflects the prices of the underlying securities. However, there are times when ETF price deviates from its fundamental value. This is called trading at a premium/discount. This creates arbitrage opportunity, which is actually being studied in finance literature. In general a stock can open at absolutely any price with no regard for the closing price or after hours price the previous day. The opening price will be determined by the best bid and offer made by people who decide to trade the next day.  Some of the those people may have put orders in on a prior day that are still on the books and matter, but there's a lot of time overnight for people to cancel orders and enter new ones, which is especially likely to happen if there was substantive news overnight. As for what you can do in your case, you have the same options that you always had:  Sell or hold.  If you're selling, you can sell after hours, in the pre-open hours, or during the trading day.  There's nothing we can say about this case that's really any different than we can say about any other stock on any other day. A few observations - A limit order can certainly work, as you've seen.  I've put in such an order far beyond the true value, and gotten back a realistic bid/ask within 10 minutes or so. That at least gave me an idea where to set my limit.  When this doesn't work, an exercise is always another way to go. You'll get the full intrinsic value, but no time value, by definition.  Per your request in comment - You own a put, strike price $100. The stock (or ETF) is trading at $50. You buy the stock and tell the broker to exercise the put, i.e. deliver the stock to the buyer of the put.