What Leon said... think about stocks, do you always hold a stock until you can sell it for a profit?
This would make the seller a "day trader" of baseball cards (of sorts) - Doesn't seem like a good strategy to buy something you may not know much about. No, sometimes you sell a stock to free up cash to buy something else. I think baseball card collectors do that to some extent, to free up money to get another card; and ball card speculators are all the time selling cards to get money to buy more cards to sell.
I'm glad ball card collectors sell cards, that puts cards out there on the market for me to have a chance at buying. Card speculators churning around in the ball card market does annoy me a bit, probably for no good reason.
Yes, this also annoys me, especially when it's something I collect and someone that doesn't care about the cards buys it thinking they can make a profit on it... it was nice to see this seller take a $200+ bath on this. Maybe next time they'll leave the bidding to people ("collectors") that actually would like to advance their collections.
One more aspect... how certain are you the the guy selling for a loss is the same guy that won the card at auction 2 months previously? There could have been an intervening transaction.
Then who ever valuated the card did a pretty poor job. It was never said that there is something suspicious about the transaction - just a really odd way to do business.
I've sold a few E90-1s at a slight loss. I didn't buy them in the first place with the intent of making money on them, I was looking at putting a set together.
This was a single card, not a "lot" of cards. Back in the day, the Mitchell card was the really tough card. But what it took to buy one was eclipsed by a few of the HOFers eventually. I think this was because there were more buyers (not just collectors) buying pre war HOFers. Look at the cost of the Mitchell (among the E90-1's I sold) back in 1990 compared to the cost of an E90-1 Cy Young, then look at the cost today... a collector eventually wants Mitchell to fill the set; a HOFer speculator has no need for a Mitchell. Compare the 1990 cost of a T206 green Cobb, to the 1990 cost of the Polar Bear Demmitt's and O'Hara's; compare that to the differential in their 2021 costs. Demmitt and O'Hara are less plentiful, yet Cobb costs much more and the cost has increased at a greater rate. I sold those few E90-1's because I had realized that I wasn't going to pay what I deemed high prices for the HOFers in the set that I lacked... Not a bit of that thought process is in the head of a speculator in old ballcards (they may think of themselves as investors, speculator seems the proper label to me).
An afterthought, maybe that 2 month later bidder was a shill bidder.
That was never said/mentioned in the initiating post... 