Allocated gold means the gold is your property and you are the legal owner of the gold. Allocated gold accounts use your funds to buy and store physical gold in secure, insured vaults. The gold stays in the vault and cannot be used for any other purpose.
When you buy with HelloGold, you are the legal owner of the gold and HelloGold is the custodian. You pay HelloGold to store it for you and not matter what happens, your gold is protected if HelloGold closes down for any reason.
With unallocated gold, many feel it is more risky. Unallocated gold accounts do not have to physically store your gold. Your gold may be lent out during the time that the company or bank holds the gold on your behalf. If the gold provider goes bankrupt, all you will have is the promise to give you back your gold – which will leave you waiting in line with other creditors.