It's not inherently fraudulent to sell something for below market value.
If I sell something I bought for $1 million for $1 in an arm's length transaction, I'm realizing a loss of $999,999 even if the asset was worth $500,000. And it'd be a rational decision if it cost me $5 million in opportunity costs to do that $500k sale.
That's not how US capital gains tax law works. It's legal to sell something at below market value, but you have to use the fair market value when calculating a loss for tax purposes. Of course some people cheat.
> When you sell a capital asset, the difference between the adjusted basis in the asset and the amount you realized from the sale is a capital gain or a capital loss.