Can I sell part of my business now and keep running the rest?

Yes, and this is a fairly common structure — selling a specific division, product line, or set of assets while keeping the rest of the business under your ownership. Because it's a partial asset sale rather than a sale of the whole company, you and the buyer identify exactly which assets, contracts, and (if any) employees are moving to the buyer, and everything not included simply stays with you and continues operating as before.

The nuance is drawing that line cleanly. Shared resources — a lease covering the whole premises, employees who split time across both parts of the business, contracts that cover the entire operation rather than just the part being sold — need to be untangled carefully, or you risk the buyer inadvertently acquiring, or you inadvertently losing, something you meant to keep. If the part being sold represents all or substantially all of the corporation's assets rather than a genuinely separate piece, it can also trigger a shareholder approval requirement under the Business Corporations Act.

Because the boundary between what's sold and what's kept is where most disputes in this kind of deal start, it's worth having a business lawyer draft the asset purchase agreement with that separation clearly defined from the outset.