Stock Price Changes In Different Time Zones

[THAIPHUKET]

Example = stock XYZ price at NASAQ closing on Friday 10$

Various Middle East exchanges are open over the weekend, possibly causing price fluctuations

Come Monday, Australia, Asia, Europe, all open before NY, i.e new prices again potenialy with big moves

How do I know at what price XYZ will open in NY?

How can I set a realistic limit order with my bank in Europe? Use their price, wait until NY opens?

Is there a source which follows a stock price around the globe? Asking just out of curiosity.

Edited May 26, 2013 by THAIPHUKET

[PCA]

all NASDAQ shares trade as well pre- and after market. Regardless also any other share trading at any exchange cannot be predicted at which price it finally will open into the next ordinary trading session.

At least not to a retail trader. There are price arrangement made in advance between for example an institution (bank, insurance company, hedge fund, very large trader) the market makers of a particular share and the stock exchange by itself to clear big block orders. But this is insider information not available, strictly forbidden and therewith not really existing or is it?

[THAIPHUKET]

PCA thanks for prompt reply! I guessed that much but now I know for sure. So the answer is to wait until NY opens and to check if the stock price is still within an acceptable range.

Alternatively placing a blind order with questionable result.

[PCA]

PCA thanks for prompt reply! I guessed that much but now I know for sure. So the answer is to wait until NY opens and to check if the stock price is still within an acceptable range.

Alternatively placing a blind order with questionable result.

yes you either wait until the opening or you can already have a parked Buy/Sell Stop Limit order at a specified price. In case the price at the opening gaps (opens below your sell stop order or above your buy stop order) you will not get filled instantly but only if the stock retraces to your specified limit price. In a fast market that bears the risk that you do not get a fill at all if it opens within your wanted price range and trades very fast through your (limited) price. But to avoid that after having seen the opening range printed you can then convert the buy/sell stop limit to a simple buy/sell stop order. Hope that does not confuse you.

[Genericnic]

PCA thanks for prompt reply! I guessed that much but now I know for sure. So the answer is to wait until NY opens and to check if the stock price is still within an acceptable range.

Alternatively placing a blind order with questionable result.

You can follow the pre-market and after hours market quotes at http://www.nasdaq.com/symbol/aapl/premarket and http://www.nasdaq.com/symbol/aapl/after-hours respectively. You can add the stocks you want to follow by using the "edit symbol list" to the left.

David

[THAIPHUKET]

Wonderful, both hints, the links are easy, David but the elaboration by
PAC requires more of my sun burned brain and a second reading :-)

[PCA]

Wonderful, both hints, the links are easy, David but the elaboration by

PAC requires more of my sun burned brain and a second reading :-)

lol - yes might seem so. Learn the rules then learn to bend them then get back into the sun and fry your brain again. Then sober up and trade what you see only and adjust your plan if necessary. Like driving a car (sensual). Then sun again

[yoshiwara]

It is not the same stock trading across different time zones otherwise you would expect the price to move in lockstep when the different exchanges are open at the same time, so for example HSBC is quoted on the Hang Seng, FTSE and NYSE and both FTSE and NYSE overlap and there is I think a 1-hour overlap on HS/FTSE in summer time. There is of course strong correlation but don't expect 1:1. If say you hold HSBc in Europe then you might get up at 7am to look at 0005 performance on the Hang Seng to inform you and during the FTSE trading hours look at the NYSE futures prior to NYSE opening, though these indicators can be treacherous. You could also set up a portfolio on Google Finance just to track the 3 shares together and get an idea of performance variation.

Edited May 26, 2013 by yoshiwara

[PCA]

It is not the same stock trading across different time zones otherwise you would expect the price to move in lockstep when the different exchanges are open at the same time, so for example HSBC is quoted on the Hang Seng, FTSE and NYSE and both FTSE and NYSE overlap and there is I think a 1-hour overlap on HS/FTSE in summer time. There is of course strong correlation but don't expect 1:1. If say you hold HSBc in Europe then you might get up at 7am to look at 0005 performance on the Hang Seng to inform you and during the FTSE trading hours look at the NYSE futures prior to NYSE opening, though these indicators can be treacherous. You could also set up a portfolio on Google Finance just to track the 3 shares together and get an idea of performance variation.

and then there is one more thing in between - currency exchange because using your sample they do trade in the currency of the country where they are listed at the (appropriate) exchange. Anyway that was a trading question based on chart reading (and order properties) purely. Portfolios are for investors, traders make or lose money as soon as they have entered at the place they are acting and nothing else.

[yoshiwara]

PCA, on 26 May 2013 - 23:57, said:

yoshiwara, on 26 May 2013 - 23:45, said:

It is not the same stock trading across different time zones otherwise you would expect the price to move in lockstep when the different exchanges are open at the same time, so for example HSBC is quoted on the Hang Seng, FTSE and NYSE and both FTSE and NYSE overlap and there is I think a 1-hour overlap on HS/FTSE in summer time. There is of course strong correlation but don't expect 1:1. If say you hold HSBc in Europe then you might get up at 7am to look at 0005 performance on the Hang Seng to inform you and during the FTSE trading hours look at the NYSE futures prior to NYSE opening, though these indicators can be treacherous. You could also set up a portfolio on Google Finance just to track the 3 shares together and get an idea of performance variation.

and then there is one more thing in between - currency exchange because using your sample they do trade in the currency of the country where they are listed at the (appropriate) exchange. Anyway that was a trading question based on chart reading (and order properties) purely. Portfolios are for investors, traders make or lose money as soon as they have entered at the place they are acting and nothing else.

First point re currency good. I am not sure I fully get that second point re traders/investors. One thing that is worth saying is that if say the stock has dived 10% on the NYSE, then setting a stop loss of less than that for when the FTSE opens will not get executed if the opening price jumps the stop. Even day-trading can encounter unfulfilled stop-loss if there is no buyer at that particular stop-loss point...which points to confining trading to liquid stocks to assist when such critical situations encountered of buyers across the board are doing a runner. No guarantee but better chance if/when a crash occurs. Edited May 26, 2013 by yoshiwara

[PCA]

PCA, on 26 May 2013 - 23:57, said:

yoshiwara, on 26 May 2013 - 23:45, said:

It is not the same stock trading across different time zones otherwise you would expect the price to move in lockstep when the different exchanges are open at the same time, so for example HSBC is quoted on the Hang Seng, FTSE and NYSE and both FTSE and NYSE overlap and there is I think a 1-hour overlap on HS/FTSE in summer time. There is of course strong correlation but don't expect 1:1. If say you hold HSBc in Europe then you might get up at 7am to look at 0005 performance on the Hang Seng to inform you and during the FTSE trading hours look at the NYSE futures prior to NYSE opening, though these indicators can be treacherous. You could also set up a portfolio on Google Finance just to track the 3 shares together and get an idea of performance variation.

and then there is one more thing in between - currency exchange because using your sample they do trade in the currency of the country where they are listed at the (appropriate) exchange. Anyway that was a trading question based on chart reading (and order properties) purely. Portfolios are for investors, traders make or lose money as soon as they have entered at the place they are acting and nothing else.

First point re currency good. I am not sure I fully get that second point re traders/investors. One thing that is worth saying is that if say the stock has dived 10% on the NYSE, then setting a stop loss of less than that for when the FTSE opens will not get executed if the opening price jumps the stop. Even day-trading can encounter unfulfilled stop-loss if there is no buyer at that particular stop-loss point...which points to confining trading to liquid stocks to assist when such critical situations encountered of buyers across the board are doing a runner. No guarantee but better chance if/when a crash occurs.

there is the difference between the order types. The stop order in case it is a simple buy/sell stop order will get executed as soon as the the market is open(also premarket if the stock for example is listed on the NASDAQ) at the very next available price matching required size and it can be at any average price (sharp, splitted and even only partly executed) depending on the way how the market is made(there are many ways) and absolutely ignorant to gap openings if there is no pre- or 24h market. Now the stop order will give you a fill as soon as there is a match available while the stop limit order provides you with the risk of not getting filled at all in case there is a gap below or above the specified(limit) price. Both order types are not providing guaranteed protection against risk. Account risk and general market risk. Any sort of stop loss order parked in the market doesn't provide safety(fill at or near your wanted price). This question was probably meant as an entry order hence my reply was not furthergoing. Stop loss orders can get filled or not but never can they control the risk you want to avoid in the first place.

Then there is the stop limit order which insists on a certain price but not size(fully or partly filled is not a criteria - whatever is available will get filled)

[yoshiwara]

PCA, on 26 May 2013 - 23:57, said:

yoshiwara, on 26 May 2013 - 23:45, said:

It is not the same stock trading across different time zones otherwise you would expect the price to move in lockstep when the different exchanges are open at the same time, so for example HSBC is quoted on the Hang Seng, FTSE and NYSE and both FTSE and NYSE overlap and there is I think a 1-hour overlap on HS/FTSE in summer time. There is of course strong correlation but don't expect 1:1. If say you hold HSBc in Europe then you might get up at 7am to look at 0005 performance on the Hang Seng to inform you and during the FTSE trading hours look at the NYSE futures prior to NYSE opening, though these indicators can be treacherous. You could also set up a portfolio on Google Finance just to track the 3 shares together and get an idea of performance variation.

and then there is one more thing in between - currency exchange because using your sample they do trade in the currency of the country where they are listed at the (appropriate) exchange. Anyway that was a trading question based on chart reading (and order properties) purely. Portfolios are for investors, traders make or lose money as soon as they have entered at the place they are acting and nothing else.

First point re currency good. I am not sure I fully get that second point re traders/investors. One thing that is worth saying is that if say the stock has dived 10% on the NYSE, then setting a stop loss of less than that for when the FTSE opens will not get executed if the opening price jumps the stop. Even day-trading can encounter unfulfilled stop-loss if there is no buyer at that particular stop-loss point...which points to confining trading to liquid stocks to assist when such critical situations encountered of buyers across the board are doing a runner. No guarantee but better chance if/when a crash occurs.

there is the difference between the order types. The stop order in case it is a simple buy/sell stop order will get executed as soon as the the market is open(also premarket if the stock for example is listed on the NASDAQ) at the very next available price matching required size and it can be at any average price (sharp, splitted and even only partly executed) depending on the way how the market is made(there are many ways) and absolutely ignorant to gap openings if there is no pre- or 24h market. Now the stop order will give you a fill as soon as there is a match available while the stop limit order provides you with the risk of not getting filled at all in case there is a gap below or above the specified(limit) price. Both order types are not providing guaranteed protection against risk. Account risk and general market risk. Any sort of stop loss order parked in the market doesn't provide safety(fill at or near your wanted price). This question was probably meant as an entry order hence my reply was not furthergoing. Stop loss orders can get filled or not but never can they control the risk you want to avoid in the first place.

Then there is the stop limit order which insists on a certain price but not size(fully or partly filled is not a criteria - whatever is available will get filled)

...the point still holding that if the price drops 50% in the previous time zone A for a company stock, then holding a 20% stop loss at end of the previous session in time zone B will not act as any limitation on the opening price drop which may be expected (though not inevitably) be in excess of that stop loss (assuming that the news event originated in time zone A).

[PCA]

PCA, on 26 May 2013 - 23:57, said:

and then there is one more thing in between - currency exchange because using your sample they do trade in the currency of the country where they are listed at the (appropriate) exchange. Anyway that was a trading question based on chart reading (and order properties) purely. Portfolios are for investors, traders make or lose money as soon as they have entered at the place they are acting and nothing else.

First point re currency good. I am not sure I fully get that second point re traders/investors. One thing that is worth saying is that if say the stock has dived 10% on the NYSE, then setting a stop loss of less than that for when the FTSE opens will not get executed if the opening price jumps the stop. Even day-trading can encounter unfulfilled stop-loss if there is no buyer at that particular stop-loss point...which points to confining trading to liquid stocks to assist when such critical situations encountered of buyers across the board are doing a runner. No guarantee but better chance if/when a crash occurs.

there is the difference between the order types. The stop order in case it is a simple buy/sell stop order will get executed as soon as the the market is open(also premarket if the stock for example is listed on the NASDAQ) at the very next available price matching required size and it can be at any average price (sharp, splitted and even only partly executed) depending on the way how the market is made(there are many ways) and absolutely ignorant to gap openings if there is no pre- or 24h market. Now the stop order will give you a fill as soon as there is a match available while the stop limit order provides you with the risk of not getting filled at all in case there is a gap below or above the specified(limit) price. Both order types are not providing guaranteed protection against risk. Account risk and general market risk. Any sort of stop loss order parked in the market doesn't provide safety(fill at or near your wanted price). This question was probably meant as an entry order hence my reply was not furthergoing. Stop loss orders can get filled or not but never can they control the risk you want to avoid in the first place.

Then there is the stop limit order which insists on a certain price but not size(fully or partly filled is not a criteria - whatever is available will get filled)

...the point still holding that if the price drops 50% in the previous time zone A for a company stock, then holding a 20% stop loss at end of the previous session in time zone B will not act as any limitation on the opening price drop which may be expected (though not inevitably) be in excess of that stop loss (assuming that the news event originated in time zone A).

yes but this is not a contradiction to what I said in the previous posts which you should be able to recognize on a second read.

[yoshiwara]

yes but this is not a contradiction to what I said in the previous posts which you should be able to recognize on a second read.

I think we have agreed that there is gap risk.

One thing I have noticed re looking at a stock quoted in 2 markets eg FTSE and NYSE is that a breaking news event in NY has on occasion provided a few seconds to trade out on the FTSE. Did it once on an announcement on Bloomberg TV.

[PCA]

yes but this is not a contradiction to what I said in the previous posts which you should be able to recognize on a second read.

I think we have agreed that there is gap risk.

One thing I have noticed re looking at a stock quoted in 2 markets eg FTSE and NYSE is that a breaking news event in NY has on occasion provided a few seconds to trade out on the FTSE. Did it once on an announcement on Bloomberg TV.

yes I think we can agree there. There is also currency risk(including interest rate consideration) and exchange risk. (trading halts or computer system crash). There could be said a lot more but I don't think that is necessary. Regardless whenever or wherever you see such news in reference to price changes in the media and even if you think it is in realtime it is already too late to make regular profit from such scenario.

[yoshiwara]

yes but this is not a contradiction to what I said in the previous posts which you should be able to recognize on a second read.

I think we have agreed that there is gap risk.

One thing I have noticed re looking at a stock quoted in 2 markets eg FTSE and NYSE is that a breaking news event in NY has on occasion provided a few seconds to trade out on the FTSE. Did it once on an announcement on Bloomberg TV.

yes I think we can agree there. There is also currency risk(including interest rate consideration) and exchange risk. (trading halts or computer system crash). There could be said a lot more but I don't think that is necessary. Regardless whenever or wherever you see such news in reference to price changes in the media and even if you think it is in realtime it is already too late to make regular profit from such scenario.

I did it once. Sold on Betty Liu and then the FTSE went down seconds later. I have streaming live prices so was able to track in real time. Market reaction isn't always instantaneous.

[PCA]

yes but this is not a contradiction to what I said in the previous posts which you should be able to recognize on a second read.

I think we have agreed that there is gap risk.

One thing I have noticed re looking at a stock quoted in 2 markets eg FTSE and NYSE is that a breaking news event in NY has on occasion provided a few seconds to trade out on the FTSE. Did it once on an announcement on Bloomberg TV.

yes I think we can agree there. There is also currency risk(including interest rate consideration) and exchange risk. (trading halts or computer system crash). There could be said a lot more but I don't think that is necessary. Regardless whenever or wherever you see such news in reference to price changes in the media and even if you think it is in realtime it is already too late to make regular profit from such scenario.

I did it once. Sold on Betty Liu and then the FTSE went down seconds later. I have streaming live prices so was able to track in real time. Market reaction isn't always instantaneous.

yes tht's possible. These days however computers are adjusting quotes fast and usually "efficient". Most what worked before doens't now except for a few things that always worked and probably always will.

So I call Betty Liu a luck shot. Luck has no constant behavior. But still you might know something I havent't thought about since I provenly saw it not regularly working anymore.

[THAIPHUKET]

What happens actually between the time my limit order is placed and final confirmation of the stock purchase? The case= I called my bank, gave order to buy x at limit 10,30. She gave it into her screen, came back to me a couple of times= still not filled. I called back after 15 min , order was confirmed at 10,23. What happened in those minutes. How does the precise matching at 10,23 work? Could have been lower or at my limit.

[PCA]

What happens actually between the time my limit order is placed and final confirmation of the stock purchase? The case= I called my bank, gave order to buy x at limit 10,30. She gave it into her screen, came back to me a couple of times= still not filled. I called back after 15 min , order was confirmed at 10,23. What happened in those minutes. How does the precise matching at 10,23 work? Could have been lower or at my limit.

It could basically be lower. You will get a ticket confirming the transaction. It will either be a tickit issued by your broker or issued by the stock exchange. If it is issued by the exchange you have what you wanted and have to accept this. If it is issued by the broker and it matches your limit price as well you have what you wanted and probably have to accept it. If at the exchange for example there would have been a better price available (for example when the market would have opened at a much better price than you specified in the limit price you still would have no right to claim compensation or a better fill towards your broker since you have already agreed and signed terms and conditions (including price making). If not you would not have qualified to open the account for its particular purpose in the first place.

I could write a book alone about this as having experienced a lot of ridiculous things with clearing order fills. In short the fewer people sit between yourself and the exchange directly the more transparent everything becomes. While I still get screwed but have negotiated myself into a commission scheme which most others don't have.

[yoshiwara]

What happens actually between the time my limit order is placed and final confirmation of the stock purchase? The case= I called my bank, gave order to buy x at limit 10,30. She gave it into her screen, came back to me a couple of times= still not filled. I called back after 15 min , order was confirmed at 10,23. What happened in those minutes. How does the precise matching at 10,23 work? Could have been lower or at my limit.

It could basically be lower. You will get a ticket confirming the transaction. It will either be a tickit issued by your broker or issued by the stock exchange. If it is issued by the exchange you have what you wanted and have to accept this. If it is issued by the broker and it matches your limit price as well you have what you wanted and probably have to accept it. If at the exchange for example there would have been a better price available (for example when the market would have opened at a much better price than you specified in the limit price you still would have no right to claim compensation or a better fill towards your broker since you have already agreed and signed terms and conditions (including price making). If not you would not have qualified to open the account for its particular purpose in the first place.

I could write a book alone about this as having experienced a lot of ridiculous things with clearing order fills. In short the fewer people sit between yourself and the exchange directly the more transparent everything becomes. While I still get screwed:P but have negotiated myself into a commission scheme which most others don't have.

I am not sure what the problem is. If the price is say 10 and I issue an order to buy at 9, then if the price hits 9 my order will be executed when it hits 9 even if the price then continues to drop further till 8,7 and so on.

[THAIPHUKET]

Thanks, PAC, I hesitated at first to pose the question, seemed so naive. What caused the question in the first place= I got irritated because my limit order was higher than the screen price at that time, therefore I thought it should be executed right away. The wait for execution literally speaking made me nervous and I increased the limit, hence I paid to much as you explained. This is not a problem Yoshiwara, but I wanted to understand. And as PAC is saying there is a lot more going on in these minutes than meets the eye. Might be a good read that book!

[PCA]

Thanks, PAC, I hesitated at first to pose the question, seemed so naive. What caused the question in the first place= I got irritated because my limit order was higher than the screen price at that time, therefore I thought it should be executed right away. The wait for execution literally speaking made me nervous and I increased the limit, hence I paid to much as you explained. This is not a problem Yoshiwara, but I wanted to understand. And as PAC is saying there is a lot more going on in these minutes than meets the eye. Might be a good read that book!

What you see on the screen is (in your case) the last price where a trade took place. I does for example not mean that your limit buy price is possible to get filled in case the bid/ask price at the same time does not make a fill possible for your order(because there is no match in the order book and as well nobody of the market makers is willed to take the other side of the trade). So I reckon in case this is a stock (but doesn't really matter if any other exchange traded product) it is either a very illiquid stock (market) with large bid/ ask spread our you are seeing delayed data on your screen. Since you have to order via phone which you stated it is most likely one of those scenarios, possibly both. Regardless as soon as you have a confirming ticket in your hands you can find out.

Edit:

there is no question too naive in this field, well there is one but that goes for most other things as well: the question that doesn't get asked.

Edited May 29, 2013 by PCA

[PCA]

What happens actually between the time my limit order is placed and final confirmation of the stock purchase? The case= I called my bank, gave order to buy x at limit 10,30. She gave it into her screen, came back to me a couple of times= still not filled. I called back after 15 min , order was confirmed at 10,23. What happened in those minutes. How does the precise matching at 10,23 work? Could have been lower or at my limit.

It could basically be lower. You will get a ticket confirming the transaction. It will either be a tickit issued by your broker or issued by the stock exchange. If it is issued by the exchange you have what you wanted and have to accept this. If it is issued by the broker and it matches your limit price as well you have what you wanted and probably have to accept it. If at the exchange for example there would have been a better price available (for example when the market would have opened at a much better price than you specified in the limit price you still would have no right to claim compensation or a better fill towards your broker since you have already agreed and signed terms and conditions (including price making). If not you would not have qualified to open the account for its particular purpose in the first place.

I could write a book alone about this as having experienced a lot of ridiculous things with clearing order fills. In short the fewer people sit between yourself and the exchange directly the more transparent everything becomes. While I still get screwed:P but have negotiated myself into a commission scheme which most others don't have.

I am not sure what the problem is. If the price is say 10 and I issue an order to buy at 9, then if the price hits 9 my order will be executed when it hits 9 even if the price then continues to drop further till 8,7 and so on.

theoretically yes, practically not necessarily.

[yoshiwara]

What happens actually between the time my limit order is placed and final confirmation of the stock purchase? The case= I called my bank, gave order to buy x at limit 10,30. She gave it into her screen, came back to me a couple of times= still not filled. I called back after 15 min , order was confirmed at 10,23. What happened in those minutes. How does the precise matching at 10,23 work? Could have been lower or at my limit.

It could basically be lower. You will get a ticket confirming the transaction. It will either be a tickit issued by your broker or issued by the stock exchange. If it is issued by the exchange you have what you wanted and have to accept this. If it is issued by the broker and it matches your limit price as well you have what you wanted and probably have to accept it. If at the exchange for example there would have been a better price available (for example when the market would have opened at a much better price than you specified in the limit price you still would have no right to claim compensation or a better fill towards your broker since you have already agreed and signed terms and conditions (including price making). If not you would not have qualified to open the account for its particular purpose in the first place.

I could write a book alone about this as having experienced a lot of ridiculous things with clearing order fills. In short the fewer people sit between yourself and the exchange directly the more transparent everything becomes. While I still get screwed:P but have negotiated myself into a commission scheme which most others don't have.

I am not sure what the problem is. If the price is say 10 and I issue an order to buy at 9, then if the price hits 9 my order will be executed when it hits 9 even if the price then continues to drop further till 8,7 and so on.

theoretically yes, practically not necessarily.

If the price is dropping on a liquid stock and the buy order is of 'normal' quantity then yes it will.

[PCA]

I am not sure what the problem is. If the price is say 10 and I issue an order to buy at 9, then if the price hits 9 my order will be executed when it hits 9 even if the price then continues to drop further till 8,7 and so on.

theoretically yes, practically not necessarily.

If the price is dropping on a liquid stock and the buy order is of 'normal' quantity then yes it will.

yes in case price and size matches your order. If only price does you might get a partly fill only.

[yoshiwara]

yes in case price and size matches your order. If only price does you might get a partly fill only.

Surely if the price drops to 9 and your order could not be fully met then the price stops dropping.

[PCA]

yes in case price and size matches your order. If only price does you might get a partly fill only.

Surely if the price drops to 9 and your order could not be fully met then the price stops dropping.

yes (or your broker tries to cheat you - again )

Edited May 29, 2013 by PCA

[yoshiwara]

yes in case price and size matches your order. If only price does you might get a partly fill only.

Surely if the price drops to 9 and your order could not be fully met then the price stops dropping.

yes (or your broker tries to cheat you - again:) )

How might a broker do that as per this example?

[PCA]

yes in case price and size matches your order. If only price does you might get a partly fill only.

Surely if the price drops to 9 and your order could not be fully met then the price stops dropping.

yes (or your broker tries to cheat you - again:) )

How might a broker do that as per this example?

for example if the broker got the order filled and likes it as much as you do while he knows there is no more price following or he can just using the spread to make a quick profit scalp in case he sees opportunity and then places the order again. The difference of knowing it is if you get a confirming ticket from your broker or from the exchange. Now that niche of cheating is very unlikely to happen if you self direct trades via a trading platform having realtime quotes but more likely possible if you do not have rt quotes and dealing via phone. If you deal via phone you can limit the chance of getting cheated in such a way by using a GTC (good til cancelled) order instead of an order which expires end of day or is valid for another specified time.

Hope you don't want to learn cheating

[yoshiwara]

for example if the broker got the order filled and likes it as much as you do while he knows there is no more price following or he can just using the spread to make a quick profit scalp in case he sees opportunity and then places the order again. The difference of knowing it is if you get a confirming ticket from your broker or from the exchange. Now that niche of cheating is very unlikely to happen if you self direct trades via a trading platform having realtime quotes but more likely possible if you do not have rt quotes and dealing via phone. If you deal via phone you can limit the chance of getting cheated in such a way by using a GTC (good til cancelled) order instead of an order which expires end of day or is valid for another specified time.

Hope you don't want to learn cheating:P

I still do not see how any cheating can occur in the example I gave. You are talking in generalities. Price is 10, order is purchase at 9 and price continues to drop to 8 and 7. Whether with broker or online your order is filled. What do you mean 'he knows there is no more price following'? He doesn't know that at all.