[[f Mom buys 12K of stock and later gifts it to me at a lower price, 9K, can
Mom claim a tax loss for the 3K?]]

Nope...which is why you don't want to gift stock that has gone down in value. It would be much better for mom to sell the stock, take the loss, and give you cash.

[[ Is 9K the basis of the gift?]]

Your basis? Yes. So, if you gift the stock, NOBODY gets the loss. See why you would rather sell the stock and gift the cash??

TMF Taxes
Roy