Mumbai, April 28 -- India's second-biggest overseas acquisition was stitched together over three months of near-daily negotiations between the bidder, the seller and their bankers, said a banker aware of the details behind the transaction.

Mumbai-based Sun Pharmaceutical Industries Ltd on Monday said in an exchange filing it will acquire US-headquartered Organon & Co for about $11.75 billion. This is the largest overseas deal by an Indian company since Tata Steel acquired UK-based Corus Group for $12 billion in 2007.

The deal was always pitched at around $12 billion from both sides, with negotiations neither exceeding nor materially falling from that level, the person cited above said on the condition of anonymity.

"The deal was out in...