Calculating and Tracking Streaks with a Custom Function

With the stocks markets tanking earlier this month, I thought it’d be interesting to track their historical performance and put into perspective just how badly things have been going lately. For those that don’t know, one of my side jobs is writing articles for the Motley Fool Canada and so naturally this example attracted my interest.

However, there’s not an easy way to calculate this in Excel, and so I decided to go the route of a custom function.

What I’m going to be looking to accomplish is a way to to track how many consecutive trading days that a stock has been up or down, and then also calculate the cumulative value of those gains and losses.

If you’d like to follow along with my example, you can download the file I used here (you’ll have to save the file, open it in Excel and enable content, otherwise you’ll see NAME? errors)

Setting Up the Variables

I want the calculation to start from the bottom (the current cell) and work its way back up, since the latest results will be at the bottom. To do this I create a ‘bottom’ variable that looks like this:

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bottom = selection.Count + selection.Row – 1

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I want the user to be able to select what range they want the calculation to apply to, rather than selecting everything.

I also setup a variable for the column, which I named as offsetnum:

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offsetnum = selection.Column

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These two variables allow me to set my starting point for my calculation.

Determining if I’m Counting Negatives or Positives

The value of the starting cell will determine if I am going to be looking for positive numbers (gains) or negatives (losses), and so I setup an if statement to determine whether the first value is a gain or loss:

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If Cells(bottom, offsetnum) < 0 Then
    posneg = “negative”
Else
    posneg = “positive”
End If

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Start counting

The final step involves counting the values depending on whether I’m looking for positives or negatives:

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For counter = bottom To 1 Step -1

    If posneg = “negative” Then
 
            If Cells(counter, offsetnum) < 0 Then
                streak = streak – 1
            Else
                Exit For
            End If
         
      Else
   
            If Cells(counter, offsetnum) >= 0 Then
                streak = streak + 1
            Else
                Exit For
            End If
         
        End If
     

Next counter

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My complete function looks as follows:

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Function streak(selection As Range)

Application.Volatile
Application.Calculate

Dim bottom, offsetnum As Integer
Dim posneg As String

bottom = selection.Count + selection.Row – 1
offsetnum = selection.Column

‘Determine first value
If Cells(bottom, offsetnum) < 0 Then
    posneg = “negative”
Else
    posneg = “positive”
End If

For counter = bottom To 1 Step -1

    If posneg = “negative” Then
 
            If Cells(counter, offsetnum) < 0 Then
                streak = streak – 1
            Else
                Exit For
            End If
         
      Else
   
            If Cells(counter, offsetnum) >= 0 Then
                streak = streak + 1
            Else
                Exit For
            End If
         
        End If
     

Next counter

End Function

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