S&P 500 Drops Sears Retailer has been part of index since it began in 1957 By John Johnson, Newser Staff Posted Aug 30, 2012 7:05 PM CDT 8 comments Comments Shoppers walk into Sears in Peabody, Mass. (AP Photo/Elise Amendola) (Newser) – Observers of the S&P 500 might notice the absence of a familiar name starting Wednesday: Sears is being dropped from the index, after being a part of it since the S&P's creation in 1957, reports CNNMoney. One of the main reasons cited for the move is a bit technical, explains the Wall Street Journal: The number of Sears shares held by public investors, or the "public float," has fallen below the necessary 50% threshold for inclusion. Shares of Sears Holding Company—parent of the Sears, K-Mart, and Land's End chains— were down 8% today on the news, notes the Chicago Tribune. That's typical because mutual funds that mimic the S&P have to sell their Sears stock and buy up that of its replacement on the index. And that company is ... Dutch chemical firm LyondellBasell Industries.