Ranbaxy Laboratories rose by 2.37 per cent to settle at Rs 720.35 on the BSE. In intra-day trade, it jumped 3.46 per cent to touch 52-week high of Rs 728.
Shares of Sun Pharma went up by 1.40 per cent to end the day at Rs 928.80. During the day, it gained 2.84 per cent to Rs 942 -- its one-year peak.
Sun Pharma and Ranbaxy have got the nod for their USD 4 billion merger from US Federal Trade Commission (FTC), which terminated a key waiting period clause, paving way for the two firms to fast-track their deal.
"The early termination of the waiting period under the HSR Act satisfies one of the essential conditions to the closing of the Ranbaxy acquisition," it said.