Looking to get a tax break by investing in a fixed deposit? Here are a few things you should know before doing that. You can get a tax deduction under 80C for investing in a fixed deposit scheme for up to 1.5 lakhs. FD's have a lock-in period of five years. Withdrawals or loans against them are not allowed. You can invest in any FD through a public or private bank. Most banks offer higher rates of interest to senior citizens.