This time, particularly in light of the data presented in the charts below, a more thorough review is provided.

Gold Bullion, the GLD ETF, and Gold Coins

The last time the chart below was updated, there wasn't really much to talk about as it was noted that the three prices seemed to track each other "rather well, going back more than a year and a half." The same can be said when looking at the chart below with two years and four months of data, though coin shop and spot prices (in green and blue) now appear to be rising above the GLD ETF (in red) just a bit.
Last time, even after looking at the differences between the three over time using moving averages (necessary because these are very noisy data series) there were no meaningful divergences. At the time I noted, "gold coins are typically $12 or $13 over the spot bid price in London and the GLD ETF x 10 works out to be around $5 less than the London close. As would be expected, the GLD ETF x 10 does show a barely noticeable trend lower relative to the spot price - on the order of one or two dollars per ounce, per year - but this seems like a reasonable price to pay since they are storing the metal for shareholders."

The chart below tell a very different story and nearly all of that story has developed since last fall.

The difference between spot gold and GLD (in red) has increased from about $5 per ounce to just over $10 per ounce and seems to have stabilized in this range - that's a significant change of over five percent of the price of gold. Looking at the information provided for the ETF (see the SPDR website for details), the fund's expenses are 0.4 percent per year, which, for $900 gold works out to be $3.60, so this is within a dollar or so of what might be expected, particularly after the stability relative to spot prices for nearly the entire year of 2007, however, it does make you stop and think.

If this trend continues (which it likely will), in addition to transaction costs, GLD holders will pay $3 to $5 per ounce per year for storage and, unless the fund's expense ratio is reduced (which it likely will), this bill will go up as the price of gold rises.