These alerts appear any time there is a print for a higher or lower price than the rest of the day.  Highs and lows are reset once a day at a time determined by the exchange.

When the alerts server sees a new high, it looks for the most recent day before today when the price was higher than it is now.  It reports the day when this happened, and the high for that day as resistance.  For a new low, the server looks for the most recent day when the price was lower than the current price.  It reports the low for that day as support.  Note:  This is a very simple version of support and resistance based only on daily highs and lows.  Several alerts listed below implement more advanced algorithms for finding support and resistance.

These alerts are related to the Position in Range filters.  Use these filters to make other alert types sensitive to highs and lows.

More options related to these alerts are listed below.

These alerts appear any time the ask price goes higher or the bid price goes lower than any time today.  These are reset at the same time as the highs and lows.  These alerts are never reported in the 30 seconds before or 60 seconds after the open.  More options related to these alerts are listed below.

These alerts are a subset of their unfiltered counterparts.  When the price quickly changes several times in a row, only one of these alerts will appear.  The unfiltered alerts appear once every time the price changes.

Typically no more than one alert per stock will appear each minute.  However, if a stock price changes by more basis points than expected, new alerts will be displayed more often.  The cutoff point for each symbol is automatically chosen based on volatility.

Daytraders often prefer to display the unfiltered versions of these alerts on a large set of stocks.  The effect is to create a window where the user can quickly see if the market as a whole is moving up or down.  Other traders prefer to see fewer, more interesting alerts.  For that effect, select these filtered versions of the alerts.  Some people create two or more alert windows, some with filtered alerts and some with unfiltered alerts.

These are similar to the new high ask (filtered) and new low bid (filtered), listed above.  More options related to these alerts are listed below.

Pre-market highs and lows show the highest and lowest prices of the morning.  This only includes the pre-market prints, which are not part of the normal highs and lows.

You can filter these the same way as normal highs and lows.  For example, set the filter to 1 if you only want to see highs which are higher than the previous day's high, or lower than the previous day's low.  More details

Post-market highs and lows show the highest and lowest prices since the market closed.  This only includes the post-market prints, which are not part of the normal highs and lows.

You can filter these alerts the same way as other highs and lows, with one difference.  We start counting the number of days from today's close.  So a value of 1 day means that the high was higher than today's high, but not higher than the previous day's high.  If that same print had happened before the market closed, it would have generated an alert with a value of 0 days.  More details

If the stock gapped down, start with yesterday's close price.  If the stock gapped up, start with today's open price.  Follow the stock down to today's low.  Report an alert when the stock returns 25% or 75% of the way from the second point back to the first point.  A stock can report these alerts more than one time per day.

Note:  These alerts examine and report on every print.  We do not filter out or otherwise correct bad prints.  These alerts are typically used as a warning of something coming, so these alerts report as quickly as possible, rather than waiting for confirmation.

Our proprietary filtering removes the most insignificant moves.  More filtering options related to these alerts are listed below.

These work just like the Pullback from lows alerts, but in the other direction.

The check mark pattern is defined by higher highs followed by lower lows followed by even higher highs.  This pattern is most commonly seen as a continuation pattern.  The inverted check mark is the same pattern, but upside down.

These patterns are based on daily highs and lows.  The exchanges report highs and lows almost exclusively during market hours, so these alerts rarely if ever occur after market.  We never report these alerts before the open or in the first three minutes after the open.  The last part of the check mark must happen at least three minutes after the open.

These alerts report when a stock moves up or down a certain percentage since the previous close.  These alerts are based on official prints, not the pre- and post-market.

These alerts were requested by money managers who often have to report to investors when a stock moves against them by too much.  These alerts are more straightforward than many of our alerts.  A money manger will typically watch several types of alerts, but will only report simple events to clients.

Typically these alerts only report once at each price level.  However, if an alert was based on a bad quote, the server will reset itself to the last valid alert.

The server does not report an alert until the stock price has changes by at least 3%.  The user can require higher standards, as described below.

These alerts report each time the stock price moves an integer number of standard deviations from the closing price.  These are very similar to the % up/down for the day alerts, but these are based on volatility rather a percentage.  For some stocks it is interesting and unusual when they move up by less than 1% from the previous close.  Others must move by 2% or more before they are interesting.  The user can require higher standards, as described below.

These alerts are slightly different from our other volatility alerts, because these use a more traditional formula for volatility.  For most of our alerts we use two weeks worth of volume-weighted, intraday volatility data, and we scale it so that "1" means a typical move for one 15 minute period.  These alerts are based on a year's worth of volatility data.  Recent data is weighted more heavily than year old data, and the data is scaled so that "1" means a standard deviation for one day.

Special thanks to our friends at Bright Trading for sharing this formula with us!

The crossed daily highs resistance alert reports whenever a stock crosses above any previous day's high for the first time since the end of that previous day.  The crossed daily lows support alert reports whenever a stock crosses a previous day's low for the first time since the end of that previous day.  These compare the current price to the daily highs and lows for the past year.

These alerts are a variation on the idea of a 5 day high or a 52 week low.  These alerts tell you when a stock is moving from 5 day highs to 6 day highs.  Or from 6 day highs to 7 day highs.  Etc.

The messages and the filters for these alerts are the same as for the new high / low price alerts.  In fact, these alerts are a subset of the standard daily high / low alerts.  These alerts only report when the number of days in the new high or low changes.

These alerts report when a stock has an unusually high number of shares on the best bid or ask.  These are very short term alerts aimed at very fast, experienced traders.

We only generate these alerts for stocks with an average daily volume of less than 1,000,000 shares per day.  We require a bid or ask size of 6,000 shares or greater to generate an alert.  We also have additional filters to prevent a stock from reporting this alert too often.  For example, if the best bid for a stock is 20,000 shares at $10.00, then someone adds a bid of 100 shares at 10.01, the 20,000 shares still appear in the order book.  When the 100 shares go away, and the best bid returns to the 20,000 shares at $10.00, we do not report another alert.

If we report a large bid or offer size, then the size grows even larger, we typically report another alert.  The message for that alert is labeled "(Size increasing)".

If a stock is showing a large bid or ask size, and the price changes but the size remains large enough, we may report an additional alert.  The message for that alert is labeled "(Price rising)" or "(Price dropping)".  This message only applies to large size.  For example, if we see a 20,000 shares on the bid at $10.00, we report an alert.  If the best bid changes to 100 shares at $10.05, we report nothing.  If the best bid then changes to 15,000 shares at $10.02, we report a second alert, labeled "(Price rising)".

If a large bid is dropping, or a large ask is rising, this makes for a stronger alert.  If a large bid is rising, or a large ask is dropping, this may be a "head fake"; someone may be trying to trick you by showing large size in one direction, while slowly buying or selling in the other direction.  In either case, we report an alert.

The bid and the ask are two completely separate alerts.  The size or price of the bid does not influence the Large ask size alert.  The size or price of the ask does not influence the Large bid size alert.

More options related to these alerts are listed below.

The market crossed alerts appears when the ask price for a stock is lower than the bid price.  These conditions occur when the stock is unusually active and often signal a turning point.

These alerts will not appear every time the market is crossed.  Crosses often appear in groups.  The alerts server will filter these, and report the first crossing in each group.  It will report new alerts only if the size of the cross grows, or if the market has been uncrossed for several minutes before crossing again.  Some stocks, particularly the highest volume stocks, are crossed on a regular basis.  The alerts server may filter out most or all of the alerts for these stocks.

In some cases the alert server will describe the alert as "up" or "down".  This distinction is based on the primary market.  The assumption is that the primary market does not react as quickly as the ECNs.  So if the bid on an ECN is higher than the specialist's offer on an NYSE stock, many traders assume the price will move up soon.

Note:  These alerts are only intended to highlight stocks which are doing interesting things.  A crossed market is often a leading indicator of other activities.  These are not intended for arbitrage.  Crossed markets typically last for only a second or two, and disappear before most traders can take advantage of them.

More options related to these alerts are listed below.