Skip to content

Normalized Gap/Lap Indicator (NGIu/NGId, NLIu, NLId)

March 21, 2011

Gaps and Laps were formerly popularized by TradingMarkets: They represent a means of identifying a type of market pattern that isn’t explicitly captured by other indicators.  Gaps or laps up or down are large price moves that originate on the open and occur on very positive or negative news that catches the market off guard. The following set of definitions apply:

gap down:  today’s open<yesterday’s low

lap down: today’s open< yesterday’s close

gap up: today’s open> yesterday’s high

lap up: today’s open>yesterday’s close

Originally much of the research done on gaps/laps used very specific percentage criteria which was to be used across a wide variety of stocks. Generally speaking the results suggested that one should fade the direction of the gap/lap over the next few days. That is, there was a mean-reversion effect to gaps/laps. The issue that I found with the research was that the % criteria such as: “gap down<-10% then buy”, was not normalized by security which tended to lead to distortions. For a small biotech, this is actually a small gap, while for a large cap stock this is  a major-sized gap. Furthermore, a gap down of -10% in 2008 was commonplace even for large caps, while the equivalent gap for a small/volatile stock would be -50% or more. Thus, this method is begging to be normalized, and this can be done several different ways but we will stick to a simpler example for this post:


1) normalized the gap: take the current gap divided by the 10-day ATR as of yesterday’s close and compare it to all other up gaps divided by their 10-day ATR as at t-1 days from the gap.

2) rank the current normalized gap in relation to at least 50 prior up gaps, this is the NGIup

NGIdown: do the same thing just compare to prior down gaps instead

NLIup: do the same thing just compare to prior laps up instead

NLIdown: do the same thing but just compare to prior laps down instead


The normalized gap/lap indicators are ideal for use in identifying how to trade for different types of gap setups. It is recommended that you look at extremes such as >80th percentile, or at the very least>50th percentile/median to conduct your analysis. Don’t have any preconceived notions about how gaps or laps should behave. Research indicates that this can be very much stock specific, and also category specific (ie small cap versus defensive large cap). On balance, there should be a mean-reversion effect, but this will vary depending on whether you are looking at up or down gaps/laps and also the magnitude of the gap/lap and the longer-term trend etc.

8 Comments leave one →
  1. Yaba Qi permalink
    March 21, 2011 4:24 am

    Hi David,

    Do you know why you are a genius? Because, when we read your posts, your ideas seem so simple, so natural, so easy to understand and to apply, so rational, to us. But also they are original, genuine and so refreshing.

    Thank you,

  2. david varadi permalink*
    March 21, 2011 1:29 pm

    Thank you Yaba, your comment is much appreciated. I try my best to keep thing conceptual as you suggest.
    kind regards,

  3. Mike permalink
    March 21, 2011 3:42 pm

    Its great to see the recent activity. Great ideas as always!

    • david varadi permalink*
      March 22, 2011 3:33 am

      thanks Mike, much appreciated. looking forward to contributing some more.

  4. Mike permalink
    March 22, 2011 12:31 am

    Your definitions look to be messed up. You’ve defined gap down twice, with contradictory definitions, and have not defined lap up at all. Definitions, as used by TradingMarkets, can be found here:

    • david varadi permalink*
      March 22, 2011 3:33 am

      thanks mike, i did indeed mix up the titles while the definitions were laid out as i had planned. thanks for the heads up.


  1. Strategy review: Fading the UP-GAP | Engineering Returns
  2. Strategy review: Fading the UP-GAP

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: