That's not quite accurate.
The folks who owned Jefferson's debt owned his assets - including the slaves within his purview.
Jefferson died deeply in debt.
"OUR LIVES, OUR FORTUNES, AND OUR SACRED HONOR"
While Jefferson lived, he owned a total of nearly 700 slaves over his lifetime. It is true that after his death, the slaves at Monticello and other Jefferson estates were sold to repay nearly $100,000 in debts.