Stock markets this week may see volatile trading sessions and a few knee-jerk reactions following the launch of GST even it is expected to take cues from announcement of macroeconomic data, say experts.

"Investors will be closely watching how the GST implementation proceeds. Investors will be keenly awaiting minutes from the Federal Open Market Committee's June meeting," VK Sharma, Head of Business PCG, HDFC Securities said.

The Goods and Services Tax (GST) — India's biggest tax reform since independence — came into force on July 1 after 17 years of debate.

"The new regime is expected to re-colonize India's tax system but may face some initial hiccups on the implementation front. With valuation over-stretched, market is now facing selling pressure on lack of new growth triggers. We believe that GST could be one of the hooks that the market will justify for correction to set in," Vijay Singhania, Founder- Director, Trade Smart Online said.

This week would also see stocks reacting to monthly auto sales numbers, he said adding global cues, crude oil and currency activity will also act as key factors that will dictate the direction.

"GST is likely to result in a near-term disruption as this is a massive reform which is getting implemented in our economy," Mayuresh Joshi, Fund Manager, Angel Broking said.

"We expect markets to remain volatile and track the management commentary on how they are adjusting to the issues arisen due to the GST," Joshi said.

Sector-specific movement can be seen after the launch of the much-awaited GST, experts said.

"One nation one tax is likely to be taken positively on Dalal Street on account of more clear taxation. Though we cannot rule out initial knee-jerk reaction. Further, auto stocks will also remain in the radar on the back of their monthly sales numbers. PMI data is also scheduled to be declared which will show the sign of macro economic activity happening," Abnish Kumar Sudhanshu, Director & Research Head, Amrapali Aadya Trading & Investments said.

On the macro front, PMI data on manufacturing and services sectors will also have a bearing, experts added.

"Market is at the doorstep of new indirect tax system.

Investors' sentiment and expectation may not be met in the short-term. But it will be positive for listed entities over the medium to long-term," Vinod Nair, Head of Research, Geojit Financial Services said.

However, more than the domestic factors, it is the global risk that haunts us more, he noted.

Last week, the Sensex recorded a fall of 216.60 points, or 0.69 per cent, while the broader Nifty lost 54.05 points, or 0.56 per cent.