Pershing Square Capital Management's activist investor has concentrated his fund into three prominent businesses.The amount of data available to investors can sometimes feel overwhelming. Between near-daily economic data releases and earnings season (the six-week period where most S&P 500 companies reveal their operating results), it can be easy to overlook something of importance.For example, investors might have missed the filing of Form 13Fs with the Securities and Exchange Commission on Aug. 14. A 13F i ...