Deposit match bonuses in online casinos are promotional offers that match a player's initial deposit up to a certain percentage, effectively increasing their bankroll. For example, if a casino offers a 100% deposit match up to $200, depositing $200 would give the player an additional $200 in bonus funds. These bonuses often come with wagering requirements, meaning players must bet a certain amount before they can withdraw any winnings derived from the bonus. This incentive encourages new players to join and existing players to continue playing, enhancing the overall gaming experience.