S&P 500 Replacements
2002, Journal of Portfolio Management
Messod Daniel Beneish, Robert E. Whaley
Standard & Poor's has become increasingly aggressive in deleting stocks from the S&P 500 index. Where once it made replacements in the index only when a particular stock had to be removed due to merger or acquisition, corporate restructuring, and bankruptcy filing, S&P now voluntarily removes a company for a variety of reasons, which may include low market capitalization, low share price, dwindling market share, or simply the need to find a spot for an up-and-comer. There are a variety of impacts on share price and trading volume for stocks added to and deleted from the S&P 500 during the period Jan. 1996 through -Dec. 2001. For additions, abnormal returns and trading volumes are higher than ever. For deletions, share prices are dealt a crippling blow.
Beneish, Messod D. and Robert E. Whaley (2002), "S&P 500 Replacements," Journal of Portfolio Management, pp. 1-10.