Median recorded eBay sale price for each quarter with 3 or more sales. Dashed line marks the 2026 retail price.
Investment scorecard
Momentum50Measured price direction: the median recorded sale of the last 4 months against the median of 8 to 12 months ago. 50 means flat; small samples are pulled toward 50.
Liquidity55How easily it sells: recorded sales in the last 12 months (300 or more scores 100) and eBay's 90-day sell-through rate.
Scarcity24Demand against supply. For modern pieces, how far the market sits above or below current retail, plus a lift if production has ended. For vintage, how rarely one comes up for sale.
Value entry67Where the latest quarter's median sale sits inside its own 3-year range. Buying near the low scores high; buying at the high scores low.
Condition safety70How safe a typical example is: the age of the design, plus how tightly sale prices cluster (a wide spread means condition and originality swing the price).
The story
The 40 mm Ballon Bleu, added in 2019 between the 36 and 42 mm sizes.
It sells far less often than the 42 and 36 on the resale market.
Also sold under reference WSBB0061; every one of them is counted here.
Our verdict: Sells for about 37% under its $8,200 boutique price. 14 recorded eBay sales in the last 12 months, with prices flat over the year.
Configurations
Sizes
40mm
Case & bracelet
Stainless steel
Factory bracelet
Steel bracelet, interchangeable, deployant
Factory bezels
Notable dials
silvered guilloche (WSBB0039) or blue sunray (WSBB0061), Roman numerals
How much is a Cartier Ballon Bleu 40mm WSBB0039 worth?
Recorded eBay sales from the last 12 months put the typical Cartier Ballon Bleu 40mm WSBB0039 at $4,500, with the middle half selling between $3,900 and $5,200 (22 sales). Condition, box and papers move the price within that range.
Does the Cartier Ballon Bleu 40mm WSBB0039 sell above retail?
No. The typical sale of $4,500 is about 45% below the $8,200 retail price.
Is the Cartier Ballon Bleu 40mm WSBB0039 a good investment?
The Crown Index grades it D- (48/100) from real resale data, and today's call is wear, not invest. Weak resale; buy it to wear, not to make money. Past prices are not a forecast.