Leads Discrepancy When Filtering Email Address Contains ‘@‘ In Smart Lists


  • When searching or grouping a list of leads based on email address filter ‘Contains’ @ sign, you may encountered the different numbers in the ‘People’ tab (result).


This behaviour is specific to the email filter as it uses two main indexes; we’ll call them Index 1 and Index 2 when using the contains/not contains operator.
  1. Index 1 searches for the entire email address value from beginning to end. This Index is used when the @ character is not included in the list of values.
  2. Index 2 searches only for the domain half of the address, which comes after the @ symbol. This Index is used when the @ character is included in the list of values.


  • A suggestion is to create a smart list with two Email Address filters wherein you will have all the ones that do not have the '@' symbol, and for the other, you will include the '@' symbol for the email address and use the logic as 'Any'. That would give you the preferred number of leads in your smart list.

Root Cause

  • Marketo database searches for email domains in a way that when using the 'contains' keyword in the 'Email Address' filter, you must make sure that if you are using the '@' symbol in your list of domains that all email domains contain this. If you want to filter for email domains that do not include the '@' symbol, you must make sure that no email domains in your list use the '@' symbol.
  • This behaviour happens when the indexing of the database and the rules that apply to the contains operator.