I just read an article about the current stock market. I will not provide a link to because there is no reason to shame the author. The general premise of the article was “The stock market is so HOT right now! The S&P is up 10.25% this quarter, which puts us on track for a 41% annual return!”.

No. How is it that someone writing an article on the stock market does not even grasp the basic concept of compound interest? Although 10.25 * 4 is indeed 41, that is not the relevant calculation. The relevant calculation is (1.1025)^4 =~ 1.4775, and a 10.25% return every quarter is a 47.75% annual return. I have to assume that people are not completely ignorant, so perhaps the author is “dumbing down” the article for the audience.