A progressive slot is a slot game linked to a jackpot that increases as people play it. Part of every eligible stake feeds the prize pool, and the current amount is usually shown live on the game screen or in the casino lobby. When the jackpot is won, it drops back to its seed value and starts growing again. Many progressive slots run several tiers at once, such as mini, minor, major and grand, with the largest tier the hardest to land.
The trigger varies by game: some award the top prize for a specific symbol combination, others through a random bonus round or a jackpot wheel, and some require the maximum bet to qualify. Because part of each stake goes to the jackpot, the return from regular wins is usually lower than in a comparable non-progressive slot. Operators should check the game rules for qualifying conditions before promoting a title. See also progressive jackpot.