SSI rules limit the amount of assets and other resources you may have and still qualify for monthly payments. The assets or resources that are counted by SSI include money in the bank, investments of any kind, real estate other than a primary residence, and personal property and household goods over certain limits. SSI also counts any money or property in which you have an interest, even if you are not the sole owner. If you have a joint bank account with someone, or hold any property in joint tenancy with someone else, SSI will consider that you own the entire account or property, because you have access to all of it.
The general limit is $2,000 in assets for an individual and $3,000 for a married couple living together. But you are actually allowed more assets than these figures seem to indicate, since not all assets are counted.