"The banking industry will remain vulnerable to the volatility in gold prices, given that pawning loans form a significant part of banks' loan books, unless essential structural and regulatory changes are implemented."
The guarantee encourages banks to lend up to 85 percent of the value of gold instead of around 60 percent.
Banks that loaned money when gold prices were around 1,700 US dollars an ounce, were hit by defaults when prices fell to 1200 to 1,300 dollars an ounce.
Banks then cut back on total pawning loans in 2013 and so far in the first quarter of 2014.
Standard & Poor's expects the overall volume of pawning loans to increase with new loans.
But a cap on interest rates could lower margins along wit