Sure: if I put an offer on your house, I will go to my credit union and ask the for a mortgage that uses your house as collateral. But the difference here is that you own your house, and the only way I can buy it - the only way I can actually *get* that mortgage - is if you agree to sell it to me.
Owner-occupied homes typically have uncomplicated ownership structures. Typically, they're owned by an individual or a couple.
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