The most popular candy in the United States is M&M's. M&M's are made by Mars, Incorporated. About $673 million is spent by the American consumer on M&M's annually.
M&M's were actually named after the two individuals who invented them, both of whom had last names beginning with the letter "m." They originally were only available in a milk chocolate flavor.
The popularity of M&M's is consistent with the popularity of chocolate during Halloween. Chocolates are the most commonly purchased Halloween candy. Chocolate is also a popular candy item internationally. Cadbury Dairy Milk is the most popular candy in the United Kingdom, and Milka chocolate is the most popular candy in Germany.