I didn't have all of the stocks for the S&P 500 for 2015 and 2016 and possibly 2014 as well.
If you work with your own investment models you likely use excel to build them, but excel isn’t ideal for many reasons and it costs you in other ways. First, you need good data and it isn’t just lying around in an easy to import format. You’re either keying it in yourself or paying money for excel downloads. When you need data from numerous sources – price information, data from different statements and across multiple years - you must merge it from multiple sheets. It's a n inefficient process which can lead to data corruption. After all this data is collected and merged, models built and tested, the net result is one statistic for one company. A stand-alone number without context has limited use. To be meaningful, you need to compare it to similar companies. This is just a sample of the challenges. You need software that overcomes these problems and is designed for investment model creation. Surprise! This software exists,