This year’s frenzied rush for gold is turning out to be quite a boon for State Street Corp. The Boston-based firm’s $78 billion SPDR Gold Shares exchange-traded fund, ticker GLD, is now making more money than any other product in the $4.6 trillion U.S. ETF market. Annual revenues for the fund have jumped to about $312 million as of July 30, meaning it is out-earning the world’s largest ETF. That’s another State Street vehicle, the $288 billion SPDR S&P 500 ETF Trust (SPY), which generates about $270 million. A combination of GLD’s higher fees -- an expense ratio of 0.4% versus 0.095% for SPY -- and an almost ... (full story)