diff --git a/research/report-restricted-rating-regulator.csv b/research/report-restricted-rating-regulator.csv
new file mode 100644
index 0000000..f5550e2
--- /dev/null
+++ b/research/report-restricted-rating-regulator.csv
@@ -0,0 +1,24 @@
+min_deviation,max_deviation,default_volatility,tau,first_advantage,rating_periods_per_day,avg_deviance
+45,500,0.09,0.75,12,0.21436,0.291317
+# ---
+# Sample Blitz rating of thibault: 1829.3 (rd: 52.789, vola: 0.08004)
+# Sample Blitz rating of german11: 1424.7 (rd: 45.000, vola: 0.09986)
+# Sample Bullet rating of revoof: 1787.6 (rd: 125.192, vola: 0.08717)
+# Sample Bullet rating of drnykterstein: 2921.3 (rd: 82.219, vola: 0.07730)
+# Sample Bullet rating of penguingim1: 3113.5 (rd: 45.000, vola: 0.08118)
+# Sample Blitz rating of lance5500: 2769.0 (rd: 54.509, vola: 0.07154)
+# Sample Blitz rating of somethingpretentious: 2247.3 (rd: 45.000, vola: 0.06258)
+# Sample Blitz rating of tbest: 2427.4 (rd: 61.639, vola: 0.08204)
+# Sample Classical rating of igormezentsev: 2513.8 (rd: 64.433, vola: 0.08854)
+# ---
+# Estimated UltraBullet distribution: p1=1341.0 p10=1476.5 p50=1804.8 p90=2259.1 p99=2372.5, avg=1833.7
+# Estimated Bullet distribution: p1=882.5 p10=1190.8 p50=1753.4 p90=2224.8 p99=2576.4, avg=1732.7
+# Estimated Blitz distribution: p1=841.6 p10=1127.2 p50=1660.9 p90=2107.0 p99=2443.1, avg=1643.9
+# Estimated Rapid distribution: p1=382.5 p10=704.3 p50=1225.2 p90=1691.9 p99=1986.8, avg=1213.9
+# Estimated Classical distribution: p1=1118.8 p10=1216.0 p50=1582.3 p90=1841.1 p99=1956.5, avg=1546.1
+# Estimated Correspondence distribution: p1=1801.6 p10=1801.6 p50=1994.2 p90=1994.2 p99=1994.2, avg=1897.9
+# ---
+# Distinct players: 18198891
+# Processed encounters: 6012388632 (last at: 2024-09-30 23:59:54)
+# Total errors: 0
+# ---
diff --git a/src/rating_system.rs b/src/rating_system.rs
index 9f10703..ad0c0d8 100644
--- a/src/rating_system.rs
+++ b/src/rating_system.rs
@@ -138,6 +138,14 @@ impl RatingSystemBuilder {
         self
     }
 
+    /// Factor by which to nudge rating gains to counteract natural deflation.
+    /// Defaults to `1.02`.
+    pub fn regulator_factor(&mut self, regulator_factor: f64) -> &mut Self {
+        assert!(regulator_factor >= 0.0);
+        self.regulator_factor = regulator_factor;
+        self
+    }
+
     pub fn build(&self) -> RatingSystem {
         assert!(self.min_rating <= self.max_rating);
         assert!(self.min_deviation <= self.max_deviation);
@@ -234,7 +242,7 @@ impl RatingSystem {
 
             max_rating_delta: RatingDifference(700.0),
 
-            regulator_factor: 1.02, // XXX
+            regulator_factor: 1.02,
         }
     }
 
@@ -294,6 +302,10 @@ impl RatingSystem {
         self.max_rating_delta
     }
 
+    pub fn regulator_factor(&self) -> f64 {
+        self.regulator_factor
+    }
+
     /// Construct an initial rating for a new player.
     pub fn new_rating(&self) -> Rating {
         Rating {
@@ -460,12 +472,11 @@ impl RatingSystem {
     }
 
     fn regulate(&self, rating: RatingScalar, delta: RatingDifference) -> RatingScalar {
-        let factor =
-            if delta > RatingDifference(0.0) && rating < self.default_rating + self.max_deviation {
-                self.regulator_factor
-            } else {
-                1.0
-            };
+        let factor = if delta > RatingDifference(0.0) && rating != self.default_rating {
+            self.regulator_factor
+        } else {
+            1.0
+        };
 
         rating + (factor * delta).clamp(-self.max_rating_delta, self.max_rating_delta)
     }