Mumbai, Aug 18 (PTI) Stock markets rose sharply on Monday powered by heavy buying in auto and consumer durables stocks, buoyed by plans for big bang reforms in the GST regime by Diwali and S&P upgrading India's sovereign credit rating.

Extending the morning gains, the 30-share BSE Sensex further jumped 1,168.11 points or 1.44 per cent to 81,765.77. The 50-share NSE Nifty surged 390.7 points or 1.58 per cent to 25,022.

From the Sensex firms, Maruti zoomed over 8 per cent. Bajaj Finance, UltraTech Cement, Mahindra & Mahindra, Trent and Bajaj Finserv were among the other major gainers from the pack.

However, Larsen & Toubro, Sun Pharma, HCL Technologies and Infosys were among the laggards.

Auto stocks were in high demand, with Hero MotoCorp jumping nearly 9 per cent. The BSE auto index jumped 4.57 per cent to 56,404.06.

"There are strong tailwinds for the market with potential to take it higher. Declarations by the prime minister on the next major reforms in GST by Diwali are a big positive. S&P upgrading India’s sovereign credit rating is another major positive," VK Vijayakumar, Chief Investment Strategist, Geojit Investments Limited, said.

Prime Minister Narendra Modi on Sunday said the Centre has circulated the draft of the next-generation GST reforms among states and sought their cooperation to implement the proposal before Diwali.

Modi had announced the proposal to reform the GST law in his Independence Day speech on August 15 from the ramparts of the Red Fort.

"The expectation is that most of the goods and services will be in the 5 per cent and 18 per cent tax slabs. Sectors like autos and cement, which are presently in the 28 per cent tax slabs, are expected to benefit. TVS Motors, Hero, Eicher, M&M and Maruti are likely to respond positively to the news. Insurance companies are also expected to benefit from the GST revision," Vijayakumar added.

In Asian markets, Japan's Nikkei 225 index, Shanghai's SSE Composite index and Hong Kong's Hang Seng traded in positive territory while South Korea's Kospi quoted lower.

The US markets ended mostly lower on Friday.

Global oil benchmark Brent crude traded 0.06 per cent up at USD 65.89 a barrel.

Foreign Institutional Investors (FIIs) offloaded equities worth Rs 1,926.76 crore on Thursday, according to exchange data.

On Thursday, the Sensex climbed 57.75 points or 0.07 per cent to settle at 80,597.66. The Nifty rose by 11.95 points or 0.05 per cent to 24,631.30.

Equity markets were closed on Friday for Independence Day. PTI SUM SUM DR DR

GST reform consolidation of tax slabs aims to lower rates for select sectors and simplify compliance across supply chains. Proposed changes to the Goods and Services Tax framework envisage consolidation of tax rates into lower and mid-level slabs, aiming to reduce incidence on several high-rate industries and improve compliance. The draft circulated to states anticipates sectoral reclassification shifting certain goods and services from higher to lower slabs, with consequential effects on pricing, input-credit dynamics, administrative procedures, and downstream compliance obligations upon enactment.