What happens to my Handicap Index if I post an exceptional score?

Under Rule 5.9 of the 2024 Rules of Handicapping, when a Score Differential is much lower than your Handicap Index in effect when the round was played, your Handicap Index is reduced automatically:

• The reduction is based on the unrounded Score Differential.
• Reductions for multiple exceptional scores are cumulative.
• The reduction is applied by adjusting each of your most recent 20 Score Differentials, including the exceptional one, so it remains after your next score and dilutes over time as new scores are added. With fewer than 20 differentials, all of them are adjusted.
• Golf Canada notes that any round, competitive or recreational, can trigger this.
• The Handicap Committee may override the adjustment if it would leave your Handicap Index as an unfair reflection of your demonstrated ability, and further review notifications are generated after multiple reductions or a -2.0 reduction.