We have found that
the use of secret reserve prices caused us to earn less revenue as sellers, relative to the practice of making our reserve prices publicly known.
Making our reserve prices secret had negative effects on probability of selling a card, the number of serious bidders in the auction, and the price received from the winning bidder.
Only 46% of secret-reserve auctions resulted in a sale, compared with 70% of public-reserve auctions for the same goods. Secret-reserve auctions resulted in 0.88 fewer serious bidders per auction [...]
We can therefore recommend that sellers avoid the use of secret reserve prices.