Notice of demand triggers taxpayer obligation to pay tax, interest and penalties following assessment or deemed intimation. Notice of demand requires the Assessing Officer to serve a prescribed-form notice specifying tax, interest, penalty, fine or other sum payable after an order under the Act, and an intimation under provisions for sums determined to be payable by an assessee, deductor or collector is deemed to be a notice of demand. For income from specified securities or sweat equity shares allotted or transferred by a current employer that is an eligible start-up, the tax or interest in the notice of demand becomes payable by the assessee within a short prescribed period measured from the earliest of a post-year lapse, the date of sale of the shares, or the date the assessee ceases employment with that employer.