Fossil Inc. will replace Medco Health Solutions Inc., which is being acquired by Express Scripts Inc., in the benchmark S&P 500 index, S&P Indices said.

Richardson, Texas-based Fossil designs, develops, markets, and distributes consumer fashion accessories such as watches, wallets and handbags. It also will be added to the S&P 500 Apparel Accessories & Luxury Goods sub-industry index.

St. Louis-based Express Scripts originally announced plans to buy Franklin Lakes, N.J.-based Medco last July. On Wednesday, the companies said that the $29.1 billion deal could close as early as next week. Shareholders from both companies have already approved the acquisition, but regulators are still reviewing it.

In addition, S&P Indices said late Wednesday that BioMed Realty Trust Inc. will replace Fossil in the S&P MidCap 400 index, and Innophos Holdings Inc. will replace BioMed in the S&P SmallCap 600 index.

San Diego-based BioMed is a real estate investment trust that serves the life science industry, while Cranbury, N.J.-based Innophos produces mineral-based specialty ingredients.

The changes will take place after the close of trading on a date to be announced, S&P Indices said.

In midday trading, Fossil shares fell $1.20 to $131.45, while Medco shares rose 2 cents to $71.22. BioMed shares rose 1 cent to $18.80 and Innophos rose $1.66, or 3.5 percent, to $49.66.