in the janurary 7 greysheet the 2003 silver proof set was at a bid/ask of 28/30. And a week later on january 14 the 2003 silver proof set is know bid/ask of 45/50. What would make a proof set go up so much in a week.
Look at the bottom of the front page of a Greysheet - see the fine print ? What it explains is how they arrive the values for the coins listed. The values are determined by the reported sale prices by various dealers around the nation. So to answer your question - somebody reported sales for that particular item at that particular price. As for what made it go up - well somebody asked that much and somebody else was willing to pay it. Just that simple.
