Stacked wilds are a slot feature in which wild symbols land in vertical groups rather than one at a time. A regular wild symbol occupies a single position and substitutes for other symbols; a stacked wild does the same job but arrives in blocks of two or three, and in some games it can cover an entire reel.
Because one stack sits on several rows at once, it can complete winning combinations on several paylines in the same spin. That is why stacked wilds can lead to considerably bigger payouts than single wilds. Some games combine stacks with sticky or expanding wilds, or add extra stacks during bonus rounds.
What operators should check
Stacked wilds are a volatility lever in a slot’s maths model, so they shape how a game feels in your lobby. When you curate a slots portfolio, read each title’s paytable to see where stacks appear and whether they are limited to bonus features.