RT Journal Article SR Electronic T1 Capturing the Index Effect via Options JF The Journal of Trading FD Institutional Investor Journals SP 72 OP 78 DO 10.3905/jot.2009.4.2.072 VO 4 IS 2 A1 Srikant Dash A1 Berlinda Liu YR 2009 UL https://pm-research.com/content/4/2/72.abstract AB This article analyzes a less-known but profound impact of additions to the S&P 500: the impact on publicly traded options of the added company. The analysis shows that, in general, the changes in at-the-money option prices are profoundly higher than changes in the corresponding stock price. Comparison between the inter-index transfers and outside additions finds a far greater index effect on option prices if the underlying stocks are introduced out of the S&P 1500 index family. While it is not possible to capture most of these price changes because they happen very shortly after the announcement, the article identifies replicable trading strategies with large, statistically significant returns.TOPICS: Options, volatility measures, statistical methods