Can I sublease the space to my buyer instead of formally assigning the lease?

You can, if your lease allows subleasing, but it's legally a very different arrangement from an assignment and usually the wrong tool for a genuine business sale. In a sublease, you keep your direct lease with the landlord and simply grant your buyer occupation rights under a separate sub-agreement; the landlord has no direct contractual relationship with your buyer, and you remain fully on the hook to the landlord for the entire tenancy, including rent, for as long as the head lease continues.

An assignment, by contrast, transfers your entire remaining leasehold interest to the buyer, who then deals with the landlord directly going forward — which is what most buyers actually want, since it gives them the legal standing of a tenant rather than a sub-tenant dependent on your ongoing lease.

Subleasing instead of assigning can leave you carrying more risk for longer than you realize, and many leases restrict subleasing just as tightly as assignment anyway. A Treadstone business lawyer can confirm which route your lease actually permits and which one fits what your buyer expects.