The Birmingham-based company has already sold more than £1m in gold bullion today with sales forecast to increase ten-fold by midnight tonight.
Rob Halliday-Stein, founder of BullionByPost, said: "This is bigger than Brexit for gold sales and we're on course to hit a record £10m sales by the end of today.
"The demand is being fuelled by global uncertainty. Whatever your political views, Trump's victory equals uncertainty and gold is a hedge against uncertainty."
With gold prices up only fractionally, Halliday-Stein also said that people are investing quickly as the price is bound to rise in the days ahead.
"This is the buying opportunity of the decade because the price hasn't moved significantly yet," he said.