Gold prices have doubled in three years, prompting a global rush to build new vaults for the wealthy. Sharps Pixley's London vault is at capacity, forcing the hunt for new sites. Omar Liess of MKS Pamp plans a "substantial" vault resembling a five-star hotel for clients storing $200mn or more.

Ludwig Karl of Swiss Gold Safe notes vaults are nearly full, requiring expansion due to insurance limits up to $5bn. Central bank buying and US dollar fears fuel the rally, with gold hitting $5,595 an ounce earlier this year. A HSBC survey shows affluent investors are increasing gold allocations, with almost half planning to add holdings.

Despite volatility, the wealthy view gold as a physical safety net outside the banking system, driving demand for physical bars over ETFs.