The most cost-effective way to buy and sell gold is in the form of professional-market bullion bars, weighing 400 troy ounces (~12.5 kg) and meeting the London Good Delivery standards. This is how all other gold products start life, from coins to jewellery and microchip wire, adding costs and losing value at each stage. Platforms like BullionVault enable private investors to buy gold in large professional-market bars, benefitting from the lower costs associated with trading on the wholesale market.