Certificates of deposit have long been a staple of traditional brick-and-mortar banks. And in times past, the only place a customer would consider opening a CD was where they already banked. But the internet has changed all that, with savers now able to open a CD online at hundreds of banks and credit unions. You can now research rates much more easily by going online. As a result, traditional banks have been given a run for their money on CDs, with online-only banks and credit unions often offering the best-paying certificates. The reason credit unions often pay better than banks is due to their nonprofit nature and consequent desire to pass benefits onto their member customers. For online banks, it's their low overhead expenses—they don't need to operate, staff, and maintain physical branches—that allow them to pay higher deposit rates to attract customers. There is also a third category of CD institution, and that is the brick-and-mortar bank that also offers banking products online to customers anywhere. Some do so from their existing website, while other banks start up separate online-only subsidiaries, sometimes even with a completely different name and brand. Fortunately for CD shoppers, it doesn't matter too much whether the top-paying CD you just found is from a bank or credit union, or from a traditional vs. online bank. So long as you ensure that the bank is FDIC-insured (or the credit union is NCUA-insured), your protection as a consumer will be the same. Though a bank may operate only online, carrying the FDIC logo indicates it meets all the same regulatory standards as a physical bank. As for credit unions, it's good to be open-minded to these as well, as their rates are often among the top-ranking in any CD term, and especially long terms. The one caveat with opening a credit union CD is that you must first become a member of the credit union. This is generally easy and fast. But it may sometimes involve making a donation to an affiliated nonprofit.