Should I disclose my own valuation to a buyer, or let them form their own opinion?

There's no legal requirement either way, and reasonable sellers do it differently. Sharing your valuation, or the reasoning behind your asking price, can build credibility and speed up negotiations, since it shows buyers you've thought through the number rather than picked it arbitrarily. Withholding it keeps your full reasoning private and can give you more room to negotiate, since the buyer doesn't know exactly how you arrived at your figure or how much flexibility you might have.

The nuance is that most sophisticated buyers will form their own view regardless, using their own advisors and their own analysis of your financials during due diligence, so withholding your valuation mainly delays rather than prevents that scrutiny. What you disclose, or don't, matters less than being able to explain and support your asking price when asked — an asking price you can't explain, valuation or not, tends to undermine buyer confidence more than simply not sharing the underlying report.

If you do disclose, make sure it's consistent with everything else you've told the buyer, since a buyer who catches a valuation assumption that contradicts your own financial statements will trust the rest of your numbers less. A business lawyer can help you decide what to share and when, based on where you are in the process.