I'm a newbie. If I run a backtest for "all symbols" on the S&P500, I get 14 results for AA and 1 result for AAPL.
If I select AA and run the backtest for "current symbol", I get 17 results. If I select AAPL and run the backtest for "current symbol", I get 11 results. If I highlight any stock, and run the backtest for "current symbol", I always get > 10 results. Why are there so few results for "all symbols"?
