Every major study proves that money managers underperform versus stock indexes. As well, active managers usually have to cover a higher expense load before they contribute anything to their performance for investors.
Are there exceptions? Sure. But these exceptions are short-lived, and no one really has found a reliable formula for picking a top performing fund in advance. Past performance is no guide. Several studies have shown that, as a whole, last year's stars tend to be this year's laggards.
Janus 20, because of its high concentration in just a few stocks, is generally forced to buy larger cap issues. Therefore, it tends to move somewhat in line with the indexes.
In stock investing, diversification has a large impact on performance. For every investor who put all his/her dollars into Intel and won big, there were many others who got clobbered for "putting all their eggs into one basket."