Anyone who has ever searched for a flight or an Uber ride is probably used to seeing the advertised price change before they actually book. But this phenomenon of “dynamic” pricing is not widely known when it comes to concert tickets. Fans of Oasis found out on Saturday when the price of tickets for the British rock group’s comeback tour more than doubled in a matter of hours. UK Culture Secretary Lisa Nandy said it was “depressing to see such grossly inflated prices that exclude regular fans” and promised to look into dynamic pricing as part of a government inquiry into ticket sales. Here’s how dynamic pricing works and why it’s so widespread.

Dynamic pricing, also known as yield management and surge pricing, is a modern adaptation of the old rules of supply and demand – only thanks to technology, it’s applied in real time. Instead of re-evaluating prices annually or quarterly, companies can now adjust them almost instantly to ensure they get the highest price buyers are willing to pay at any given time. In the case of the Oasis concerts, standing room tickets were initially offered for around £150 ($197) but rose to £355 after a few hours as fans flocked to ticket websites.