Sector SPDR ETFs
Select Sector SPDRs are unique ETFs that divide the S&P 500 into sector index funds. Select Sector SPDRs have the diversification of a mutual fund, the focus of a sector fund, and the tradability of a stock. You can buy or sell Select Sector SPDR shares on NYSE Arca throughout the trading day.
Together, the nine Select Sector SPDRs represent the S&P 500 as a whole. However, each Select Sector SPDR can also be bought individually, providing you with undiluted exposure to a particular sector or industry group.www.sectorspdr.com/sectorspdr
If you are looking for the best time to get in or out the market it is a good idea to trade in the direction of the Market and research sector to understand your bias towards all sectors.
S&P Market Sectors
There are aggressive sectors and defensive sectors from a traditional standpoint. When recession or bearish times happen typically money flow out of aggressive sectors and flow into defensive sectors and the bond market.