The maximum tenure of a fixed deposit (FD) can vary depending on the bank or financial institution offering it. According to the search results, the tenure of an FD can range from 7 days to 10 years. However, long-term fixed deposits are usually held for anywhere between more than 5 years to 10 years. It is important to note that the longer the term of deposit, the higher is the rate of interest, but a bank may offer a lower rate of interest for a longer period if it expects interest rates to dip in the future.