Thanks to all for your responses. Here is the final answer that I have concluded after reading your messages and consulting with my sources. This is a recap of the final conversation I had with an institutional trader on this subject. "Some charting software utilize BOM to accommodate retail traders who use candlestick price charts for TA which makes up a large percentage of their biz. As I understand it, most candle traders prefer the time stamp at the beginning of the chart bar for various reasons which may, or may not, be valid; you'll have to ask them. In contrast, some charting software utilize EOM to accommodate institutional traders because they are more likely to perform TA on historical data and need accurate time stamps on the chart bars correlating to the real clock/time. As you have found out, all "historical" data on SC and other trading software which utilize BOM are "technically" incorrect because their respective chart bars are one-minute behind the clock and, therefore, they don't align with the actual real time that the chart bar occurred. However, it's important to note, that the "current" chart bar on all real-time trading software platforms which utilize BOM are correct with the clock, just like EOM charting software, that is, until the seconds hit 0:59 at which time, the BOM current chart bar becomes the prior chart bar and now that BOM prior chart bar is off by one-minute. As long as a person is only using one charting software like SC then, this would probably be a nothing-burger because the retail trader would never know that the historical chart bar time stamps are off by one minute unless, they referred to the open/close price which are also off by one minute in which case, that might be cause for confusion. Other than that, the problem only becomes evident when a trader uses two or more charting services that calculate their chart bar times differently, such as in your case, because the BOM and EOM historical chart bar times will not correlate unless you add one minute to the BOM historical time stamps or subtract one minute from the EOM time stamps. As far as to which method, BOM or EOM, of calculating chart bar times is industry standard? Without doubt, all the stock market indexes utilize EOM because you can't change the time on a clock. Otherwise, the markets would open at 9:29 ET and close at 3:59 ET (BOM time) which wouldn't make much sense. But that does not negate the reasons that SC or other BOM trading software companies may have chosen to utilize BOM in lieu of EOM as stated above. What is amazing is that we're even having to have this discussion in the 21st Century. You would think that the charting software companies would give you an option to choose either BOM starting time or EOM ending time which would accommodate all traders and eliminate any potential issues."
The way Sierra Chart stamps their time at the beginning of the candle is the only way that makes sense to me. Market opens at 8:30 Central.....so 8:30 central is the time the candle begins. Everything before 8:30 (8:29:59.99999999999999999) is before the market opens. Not that it matters. I'm not trying to pick a fight. I just get a little frustrated when trying to time the same bars on Ninjatrader for backtesting and I think in terms of the way Sierra Chart stamps time.
Respectfully, historical chart bar/prices and analysis thereof, does not utilize seconds but rather only minutes. And, education has taught us since time began that it's not "8:30" until 0:60 seconds has elapsed. Hence, anything before 8:30, including but not limited to 8:29:59.999999, is still 8:29.
And, in contrast to your frustration, think about all those ATP and Ninja traders who are confused by SC saying the market opened at 9:29ET and closed at 3:59ET when they know for a fact that the market hours are 9:30-4ET. I personally believe it's a matter of habit and what one is used to using. I would guess that the majority of Ninja warriors are perfectly happy with EOM or else they would have changed to BOM one would think. But you would know better than I if it's habit or not, because I don't trade candles nor do I scalp.
.. and that is exactly what SC (and all others) are doing. The "8:30" candle includes in itself all ticks timestamped from 8:30:00 to 8:30:59.99999. What is the problem with that? Using the start-of-candle timestamping and one-minute candles, the market starts with the 9:30 EST candle and ends with the 15:59 EST one. I really don't understand what the problem is.
I assume you're referring to the current (in-process) candle and not the prior (historical) candles? If you're referring to the current candle, if I was a DT, I personally wouldn't have a problem with it although, I'm not a fan of BOM for my trading style which again is not scalping or DT but rather trend trading or short-term position trading. The institutional trader clearly stated in my post above, that all real-time charting software are accurate with the real clock in the "current" bar only. That only ceases to be true when the current bar becomes the prior historical bar at which time SC and other BOM trading software becomes one minute delayed because typically historical chart bar analysis only considers minutes, and not seconds, when analyzing historical chart bars. I wasn't meaning to question the DT's here and their choice of trading software because all the "current" chart bars are the same (actual real clock time) while the current chart bar is in-process. So, again, I don't have a problem with it for DT. But rather I thought this topic might help others who perform intraday and longer-term analysis on "historical" chart bars in minutes, not seconds, as I do, so they can avoid the potential costly error of correlating different charting software that may not use the same chart bar time calculation (BOM/EOM). For example, if I am using ATP to track SPY but I'm using SC's NYSE A/D chart because it's better than ATP's NYSE A/D, IMO, my historical chart bar analysis would be incorrect if I used the same time stamp on each service because SC uses BOM and ATP uses EOM. Fortunately, I caught the mistake and now adding one minute to all SC "historical" chart bars which makes both SC and ATP historical chart bars correlate perfectly. And, before anyone mentions it, I realize that SPY does not directly correlate to the NYSE I just used that as an example as it's one of many indicators we use.
Not sure if the charts are readable or help to understand, but this is the MES at the open today. 1 second chart on the left and 1 minute on the right. As soon as the clocks in your house (assuming they keep time correctly) are at 8:30 Central Time, the new candles begin on everything from 1 second, 1 minute, 5 minute and so on.
I am confused. Help me out here. You have a chart. Last candle is "current" - all the other candles are "prior" candles. Correct? Let's say it's 9:45:33 right now. The "current" candle is timestamped 9:45. It contains ticks from 9:45 until 9:45:33. The candle immediately before it is timestamped 9:44. It contains ticks from 9:44 until 9:44:59.9999. When the current candle finishes and another candle starts at 9:46, the current candle will become a "prior" candle. But its timestamp will not change. What do you want to change in this scenario? You seem to imply that as the current candle becomes a "historical" candle - that is, when its minute is over and the new candle begins - its timestamp should change. That seems very weird to me. Am I misunderstanding you?
First, I don't want to change anything anymore because I'm having this same conversation on the SC board (finally) and you cannot change SC to EOM. And, I have my answer, so not looking for an answer anymore but always open-minded to learning. But having said that, here's the easiest way I can explain it... Actual clock time reads 10:11 (seconds in progress): SC (BOM) = prior chart bar reads 10:10:00 minutes and current chart bar 10:11 (seconds in-progress). ATP (EOM) = prior chart bar reads 10:11:00 minutes and current chart bar 10:11 (seconds in-progress) You can see above that the ATP (EOM) "current" chart bar reads the same as the SC (BOM) "current" chart bar so, both are correct when using the "current" chart bar for analysis. However, you can also see that beginning with the first "historical" chart bar that SC is already showing a one-minute delayed chart bar as compared to ATP. That's because SC ignores the seconds and does not advance to the next minute when 60 seconds elapses because they use BOM. In contrast, once 60 seconds have elapsed ATP's (EOM) current chart bar will advance by one minute and become its prior chart bar. Here's how it will look: Actual clock time reads 10:12 (seconds in-progress): SC (BOM) = prior chart bar reads 10:11:00 minutes and current bar 10:12 (seconds in-progress). ATP (EOM) = prior chart bar reads 10:12:00 minutes and current chart bar 10:12 (seconds in-progress) Summary: This is a substantial error, IMO, when you are performing historical chart bar analysis. As one would obviously want to count on the accuracy of the time stamp in minutes (as compared to the real clock), for all historical chart bars which cannot be done when using trading software that uses BOM time stamp calculations. Having to add one-minute to all SC historical chart bars or subtract one-minute from all ATP chart bars is a mistake waiting to happen. Can you imagine writing code only to find out after you've lost a small fortune that you were analyzing the wrong bar? It just about happened to me. That's why I'm posting.