Not only are gold prices rising, but the costs for storing the actual bullion have also increased.

During the recent market volatility, many nervous investors are seeking safe havens and have turned to purchasing gold, especially following the announcement by the Federal Reserve that it expects to keep interest rates low for another two years.

The price of gold surpassed $1,800 an ounce Wednesday for the first time as investors pulled their money out of stocks and snapped up precious metals contracts, the Associated Press reported. Gold is fast becoming a favorite port in a storm of uncertainty. Investors are clinging to what they see as a hedge against volatile stock and currency markets.

Banks are now charging more to store that gold because these surges in demand have left London, the center of the global bullion market, short of vault space, reported the Financial Times.

“Much of the increased demand comes from exchange-traded funds (ETFs),” the Financial Times reports. “Investors in ETFs this week boosted their collective gold holdings to about 2,300 tonnes, more than most central banks.”

The largest of the gold ETFs, SPDR Gold Trust, is an example of an entity that houses its bullion in London.

There are basically two pricing strategies for gold storage, according to GoldSilver.com. The more expensive depositories charge a percentage of the market value for the gold held. The other pricing model, which is generally considered cheaper, involves fees calculated based on physical attributes such as square footage consumed by the holding.

Almost all of the major bullion-dealing banks have raised fees since March this year, the Financial Times reported. “In some cases more than doubling the rates.”

The Financial Times also reported that some banks that were using the cheaper pricing model, calculating fees by weight, have changed their policies and are now charging fees based on value.

In response to the growing strain on the London vaulting system, both Barclays Capital and Deutsche Bank are planning to build new vaults, the Financial Times reports.