NEW DELHI: India’s changeover to the goods and services tax ( GST ) has resonated with the Fed : A research note at the US central bank reckons that the biggest indirect tax reforms since Independence could enhance the country’s gross domestic product by up to 4.2%, or Rs 6.5 lakh crore — a sum greater than the central government’s annual borrowing.Apart of Federal Reserve System’s series of International Financial Discussion Papers (IFDP), the research note says that the potential gains to GDP — one of the most bullish growth estimates on the reform measure to date — will be underpinned by a surge in manufacturing output, something New Delhi has been trying to achieve for a while.An estimate by economic think tank NCAER had earlier projected an increase of 1-2% in GDP after GST is implemented. “We find that the GST is expected to raise overall Indian welfare, and is projected to be an inclusive policy in that it would be welfare improving for all Indian states,” the paper said. The model suggests that the GST would lead to real GDP gains of 4.2% under the baseline assumptions, driven by a surge in factory production.Growth is also driven by an increase in both domestic and international trade, it said. The GST is also expected to increase the international competitiveness of Indian companies, thus helping the country expand external trade by 32%.“As a first order effect, the GST lowers internal trade barriers in this analysis, which improves internal trade by 29%....,” according to the paper authored by Eva Van Leemput and Ellen A Wiencek and published on March 24.To be sure, the authors sounded a note of caution on placing goods in higher tiers of taxation. “We also find that the distribution of goods across tax rate tiers matters for the growth outlook. As more goods move to the upper tiers, the real GDP and manufacturing output gains would be dampened,” it said.The rise in internal and external trade is expected to be carried by a surge in manufacturing production of 14%, said the paper. IFDP notes are articles in which Fed Board economists offer their own views and present analyses on a range of topics in economics and finance. In the just concluded Budget session, Indian lawmakers passed the crucial GST legislations, paving the deck for state assemblies to take up the relevant bills.The GST, which seeks to replace multiple central taxes and state taxes with a single levy, is scheduled to be introduced from July 1.