Hidden Markov models - regime detection

Standard & Poor's 500 Index (S&P 500) is an American Stock market index of 500 stocks. It is a leading indicator of US equities and reflects the performance of large-cap companies selected by economists. Experts, when determining the 500 stocks, consider factors that are included in the index, including market size, liquidity, and industry grouping. It is a market value-weighted index and one of the common benchmarks for the US stock market. Investment products based on the S&P 500 include index funds and exchange-traded funds are available to investors. Investors have a challenge replicating the S&P 500 since the portfolio would need stocks of 500 companies in ratio to the entire portfolio to replicate the index's market cap methodology. For investors it would be easier to purchase one of the S&P 500 investment products such as the Vanguard S&P 500 ETF, the SPDR S&P 500 ETF...