What happens if a working capital adjustment shows I owe the seller more money after closing?

Working capital adjustments run in both directions, so this is a normal and expected outcome, not a sign that something has gone wrong. If the final closing statement, prepared and reviewed after closing under the agreed accounting methodology, shows that actual working capital at closing was higher than the estimate used to set the price at the time, the buyer typically owes the seller a true-up payment for the difference, just as the seller would owe the buyer if the actual figure came in lower.

The purchase agreement should specify a deadline for making this payment once the final figures are agreed or determined, and often provides for interest if payment is late, similar to other deferred obligations in the deal. If the buyer disagrees with the seller's calculation of the final statement, most agreements provide a defined process for resolving that disagreement, commonly referral to an independent accountant, rather than leaving the buyer to simply refuse payment. Reviewing the calculation carefully, and raising any dispute through that process promptly, is the appropriate response rather than withholding payment outright.