The fund is based on the largest American companies, meaning it is comprised of many of the most successful companies in the world. Certificates of deposit , or CDs , are issued by banks and generally offer a higher interest rate than savings accounts. Investments issued by the U. If you put all of your money into one long-term CD and then need it back at any time, CD’s may not be the best for you. These stocks tend to be made up of tech companies that are growing sales and profits very quickly, such as Alphabet parent of Google , Amazon and Apple. This may sound like a CD, but it is different.