Concessional tax regime for domestic manufacturing companies depends on eligibility, disallowed deductions, and an irrevocable return-filing option. Optional concessional tax regime applies to specified domestic manufacturing companies incorporated in India. An eligible company may elect tax at 25% on total income, subject to surcharge, if it is set up and registered on or after the prescribed date, is engaged only in manufacture or production of an article or thing and related research or distribution of its own manufactured product, and computes income without the specified deductions, allowances, and set-off of carried-forward losses linked to those deductions. The option must be exercised by the due date for filing the first return, continues for subsequent years, and cannot ordinarily be withdrawn once exercised, except where the company opts for the alternative regime.