The BSE gauge Sensex fell 73.88 points to 35,548.26 and the NSE Nifty slid 17.85 points to 10,799.85, taking cues from tumbling global shares.
In a surprise announcement in April, Sun and Ranbaxy -- at that time owned by Japan's Daiichi -- declared an all-stock deal to create India's largest and world's fifth-largest drugmaker in an over $4 billion deal.
ITC, Sun Pharma, HDFC and Coal India were among the top gainers.
Pharma shares were the top gainers led by Lupin after the company received EIR from USFDA for its Goa facility
Financial shares were among the top Sensex gainers along with auto and pharma shares.
Market breadth ended weak on the BSE with 1,838 declines against 1,218 advances.
Market breadth was weak with 1239 losers and 1078 gainers on the BSE.
Firms generated free cash flows in 2013-14, for the first time since the 2008 Lehman crisis
Dilip Shanghvi has never tried to be everything to everybody.
In 10 sessions Sensex rose over 8%
n the broader market, BSE Midcap and Smallcap indices are trading higher by 0.3% each.
The sentiment-driven rally also got support from stock specific earning results and Finance Minister Arun Jaitley's statement that the Centre will step up reforms to attract more investment and fill up infrastructure deficit.
The S&P BSE Sensex ended the session at 25,342, up 3 points while the Nifty50 closed at 7,738 points.
Profit-booking and selling pressure on below-normal monsoon forecast, marred sentiments, traders said.
The BSE Midcap and the BSE Smallcap indices pared all intraday gains to end 0.3% and 0.5% lower
Out of 30 Sensex shares, 19 ended lower while 11 gained
The 30-share Sensex dropped 298 points to end at 27,209 and the 50-share Nifty has lost 93 points to end at 8,174.
Among the Sensex 30 stocks, new entrant Sesa Goa soared 22 per cent to Rs 187, while TCS rose 11 per cent to Rs 2,023.
Shares of L&T Technology Services, an arm of engineering giant Larsen and Toubro, made a decent debut on the bourses
The NSE Nifty, comprising 50 shares, breached the 8,300-mark for the first time to hit a new lifetime high of 8,330.75.
The 30-share BSE Sensex closed down 162 points at 28,338 and the 50-share Nifty was down 67 points at 8,463.