An adjustable-rate mortgage (ARM) is a type of home loan where the interest rate can change periodically, usually in response to changes in the market. ARMs are a popular choice for real estate investors because they often come with lower initial interest rates than fixed-rate mortgages, which can make them more affordable in the short term. However, there are also risks associated with ARMs that investors should be aware of before deciding whether to use one for their real estate investments.