Before comparing auction prices, identify exactly what each number includes. Christie’s New York online sale page explicitly says estimates exclude buyer’s premium, while sale totals combine hammer price and buyer’s premium. Sotheby’s June Fine Watches page says its listed results include Sotheby’s premiums but exclude applicable taxes and costs unless otherwise noted. These definitions should be checked for each sale. Currency, date, condition and accessories also matter. A single auction outcome is evidence of one transaction, not a guaranteed valuation or an investment return.