Can I still be liable for a lease default my buyer causes years after I've sold the business?

Yes, potentially — and this is a direct consequence of the general rule that assigning a lease doesn't automatically release the original tenant. If you assigned the lease to your buyer but never obtained a formal release from the landlord, you can generally remain liable on the lease covenants for the rest of the term, which means a default by your buyer years down the road — unpaid rent, damage to the premises, breach of another lease obligation — can still expose you, long after you've moved on from the business entirely.

This risk doesn't fade with time or distance from the business; it exists for as long as the lease term (and any renewals your guarantee or ongoing liability might cover) continues, unless a release was properly documented at the time of the sale.

If you're not certain whether you obtained a full release when you sold, it's worth confirming now rather than waiting to find out through a demand letter. A Treadstone business lawyer can review your original assignment documents and clarify where you actually stand.