Law Of Large Numbers

What Does Law Of Large Numbers Mean?
In statistical terms, a rule that assumes that as the number of samples increases, the average of these samples is likely to reach the mean of the whole population. When relating this concept to finance, it suggests that as a company grows, its chances of sustaining a large percentage in growth diminish. This is because as a company continues to expand, it must grow more and more just to maintain a constant percentage of growth.

Investopedia explains Law Of Large Numbers
As an example, assume that company X has a market capitalization of $400 billion and company Y has a market capitalization of $5 billion. In order for company X to grow by 50%, it must increase its market capitalization by $200 billion, while company Y would only have to increase its market capitalization by $2.5 billion. The law of large numbers suggests that it is much more likely that company Y will be able to expand by 50% than company X. 

The law of large numbers makes logical sense. If a large company continues to grow at 30-50% every year, it would eventually become bigger than the economy itself! Obviously, this can't happen and eventually growth has to slow down. As a result, investing in companies with very high market capitalization can dampen the potential for stock appreciation.