American Express - Cleartax Offer | AMEX IN Cleartax Terms and Conditions. Offer: Flat 25% discount applicable on all CA assisted services on Cleartax with your American Express Card. Use promo code CTAMEX25. Offer prices will be exclusive of the GST. Offer cannot be clubbed with any other offer. Offer can also be availed on Supplementary Cards. Offer valid from 8 July 2020 to 31 July 2022.