Can I sue for the difference if the business's real revenue turns out to be way lower than reported?

If actual revenue is materially lower than what the seller represented in the purchase agreement, this generally supports an indemnity claim for breach of the seller's financial representations, rather than an automatic right to unwind the whole transaction. That claim is measured against the negotiated survival period, cap, and basket that apply to the specific representation involved, so the amount actually recoverable isn't simply the full revenue shortfall by default.

Whether a broader misrepresentation claim is also available, potentially with a wider range of remedies than the ordinary indemnity mechanics allow, often turns on how the seller came to state that figure — an honest calculation error is treated differently from a number the seller knew, or should have known, was inflated. Practically, this kind of dispute frequently connects to the working-capital or closing-financial-statement mechanics discussed elsewhere, since the true post-closing numbers are usually what exposes the original gap. Identify exactly which representation the revenue figure ties back to before assuming a particular formula or amount applies.