If you bank with a credit union, you may notice a deposit appear once a year labeled something like "descriptive deposit rebate." It is not a mistake. It is one of the best-kept perks of credit union membership.
Credit unions are member-owned cooperatives, not for-profit banks. After they cover operating costs and reserves, any leftover money belongs to the members. Many credit unions return some of that surplus once a year, usually in late December or early January. This is called a patronage rebate, loan interest rebate, or bonus dividend.
How much you receive depends on your activity that year. Your rebate may depend on interest paid on loans, dividends earned on savings, sometimes debit card use. If you have a mortgage or car loan with the credit union, that is probably the main driver.
Percentages vary widely. Some credit unions return 1 or 2 percent of the interest paid. Others have returned as much as 35 percent in strong years.
It is not guaranteed every year, but many credit unions have done it for decades.