August 2, 2021
Recent U.S. tax proposals under various names (e.g., wealth taxes, estate tax reform, etc.) center on mark-to-market (MTM) taxation, which eliminates investors’ ability to defer or avoid capital gains taxes. To provide insight on potential effects of these tax proposals, we exploit a unique U.S. setting where “index” options on the S&P 500 Index (SPX) face MTM taxation whereas nearly identical “non-index” options on the exchange traded fund (ETF) tracking the S&P 500 Index (SPY) do not.