The company's board had earlier accorded approval to acquire 86% stake in SRL from promoters.
"The company on May 12, 2011, completed the acquisition of the strategic stake of 74.59% in the existing expanded equity share capital of SRL, from the promoters of SRL," Fortis Healthcare said in a filing to the Bombay Stock Exchange (BSE).
Based on the valuation of 9.27% stake sale to private equity firm Avigo Capital Partners by SRL, Fortis is expected to pay around Rs 930 crore for 86% stake in the company.
Avigo Capital Partners had picked up 9.27% stake in SRL in a pre-IPO placement for an aggregate amount of nearly Rs 100 crore.
In February this year, SRL had filed a Draft Red Herring Prospectus (DRHP) with the Securities Exchange Board of India (Sebi) for a public issue of 28 million shares and the document is awaiting comments from Sebi, it said.
As per the DRHP, promoter and promoter groups held 85.67% sake in SRL.
Super Religare Laboratories, which is one of the largest diagnostics provider in the country, acquired Piramal Diagnostic Services (PDSPL) in August 2010 for Rs 600 crore to strengthen its presence in the radiology services.
SRL's present network consists of 8 reference laboratories, 7 centres of excellence, 181 network laboratories (164 pathology, 17 radiology), 15 wellness centres and 888 collection centres.
Fortis had recently launched C-Doc for diabetes and metabolic diseases and stem cell therapy centres.
Fortis commissioned its first hospital in 2001 at Mohali, and has grown into a network of 56 hospitals with an over 8,000 bed capacity.
Shares of Fortis Healthcare today closed at Rs 156 on the BSE, down 0.64% from its previous close.