Do I need a certified cheque, or can the purchase funds just be wired directly?

In practice, purchase funds for a business sale are typically sent by wire, lawyer's trust account to lawyer's trust account, rather than by certified cheque. A wire gives the receiving lawyer immediate, verifiable confirmation that cleared funds have actually landed before closing is allowed to proceed, which is generally more convenient and reliable than a physically delivered cheque, even a certified one.

That said, what's actually required comes down to what the receiving lawyer will accept and what the purchase agreement specifies, so this isn't purely your own choice to make unilaterally. Some smaller or more traditional transactions still use a certified cheque without issue. The practical point is to confirm the accepted method, and the exact trust account details, directly with your own lawyer well before closing day — not the morning of — since a wire that hasn't been properly initiated in time can cause exactly the kind of delay discussed elsewhere, and a cheque prepared incorrectly can be just as disruptive.