Conventional loans are rarely assumable, because the mortgage contract usually contains a due-on-sale clause, which allows the lender to demand the entire remaining loan amount as soon as the property is sold. That would mean that, as soon as the buyer assumed the loan, the lender could step in and hand them a bill for hundreds of thousands of dollars. Not many buyers want to take that risk.
However, if you have a conventional adjustable-rate mortgage (ARM), it's possible that your mortgage is eligible for assumption. Fannie Mae — one of the two mortgage agencies that sets rules for conventional loans — allows for assumable ARMs as long as the borrower agrees to give up the option to convert the loan to a fixed-rate mortgage. Make sure your future plans don’t include converting to a fixed rate if you’re assuming an ARM.
In cases where a conventional ARM loan has been modified or deferred to help avoid default, it's no longer eligible for assumption.