Can I require the seller to guarantee the accuracy of the working capital figures they gave me?

Yes, and buyers commonly achieve this through the representations and warranties in the purchase agreement rather than through the working capital mechanism alone. A seller can be required to represent that the financial statements provided during the deal, and often specifically the estimated closing working capital statement used to set the price, are accurate and were prepared consistently with a stated accounting policy, giving the buyer a contractual basis to hold the seller to those figures.

If those figures later prove materially inaccurate, the buyer may have both an indemnity claim for breach of that specific representation and the benefit of the working capital true-up mechanism itself, which independently corrects the price based on the actual final figures regardless of any misrepresentation. Building this protection properly means coordinating the representations about the financial figures with the adjustment mechanic during drafting, rather than assuming the working capital process alone is enough, since the two work together to address slightly different problems: one corrects the price, the other addresses accountability for inaccurate information.