Quote from GordonTheGekko:
Note: if your system is based solely on indexes, trade the leveraged ETFs instead, or VIX futures if it's very short term (intra day) - it will turn a 4:1 margin into 18 or more. For example, VIX on an intra day basis moves tick for tick with the S&P (see attached). So trade VIX instead of SPY
That depends on what kind of liquidity he needs. The VIX follows the SPY closely but the lower the SPY gets the bigger the moves the VIX makes. When SPY recovers (bull market), the VIX gets pretty much the same, and then you're only loosing out on liquidity. For now though, most home-based traders are ok trading the VIX, so that's decent advice. I mean if volatility is required and liquidity is not a problem he may as well trade SPY options hehe (good luck with that).
Also the ES (S&P 500 futures at GLOBEX) can be traded 24/7 with an automated trading system if you leave it on, and it too follows the SPY tick for tick, and has volume which is often even better (in $ terms, not contract terms).
Another bit of advice:
The forex also runs 24/7 (well almost) and you can auto-trade it at the same time while trading equities. That's as long as you don't use margin. This is because most brokers see your buying power as unchanged during the day while you are converting back/forth between currencies. So you can make a system that trades forex with the same cash being used for trading equities/futures/index whatever. Just that forex should be traded about 2-5 times per 24 hours since it moves slower, but that's just imho, so you would need to adjust your system for those periods.
