diff --git a/crates/ml-hyperopt/src/optimizer.rs b/crates/ml-hyperopt/src/optimizer.rs
index d2f3c396e..43f3d0d17 100644
--- a/crates/ml-hyperopt/src/optimizer.rs
+++ b/crates/ml-hyperopt/src/optimizer.rs
@@ -374,8 +374,18 @@ impl ArgminOptimizer {
             let lower_bounds: Vec<f64> = bounds.iter().map(|(min, _)| *min).collect();
             let upper_bounds: Vec<f64> = bounds.iter().map(|(_, max)| *max).collect();
 
-            // Create Particle Swarm solver
-            let solver = ParticleSwarm::new((lower_bounds, upper_bounds), self.n_particles);
+            // Create Particle Swarm solver with tuned parameters.
+            // Default argmin: inertia=0.72, cognitive=1.19, social=1.19
+            // Problem: social >> inertia → premature convergence to global best.
+            // Fix: higher inertia (0.9) for exploration, lower social (0.8) to
+            // reduce collapse toward the single LHS best point.
+            let solver = ParticleSwarm::new((lower_bounds, upper_bounds), self.n_particles)
+                .with_inertia_factor(0.9)
+                .map_err(|e| anyhow::anyhow!("PSO inertia: {e}"))?
+                .with_cognitive_factor(1.5)
+                .map_err(|e| anyhow::anyhow!("PSO cognitive: {e}"))?
+                .with_social_factor(0.8)
+                .map_err(|e| anyhow::anyhow!("PSO social: {e}"))?;
 
             // Run optimization (parallel execution enabled via rayon feature)
             // CRITICAL FIX (2025-11-03): Removed .target_cost(0.0) to prevent early termination
@@ -798,7 +808,13 @@ impl ArgminOptimizer {
             let lower_bounds: Vec<f64> = bounds.iter().map(|(min, _)| *min).collect();
             let upper_bounds: Vec<f64> = bounds.iter().map(|(_, max)| *max).collect();
 
-            let solver = ParticleSwarm::new((lower_bounds, upper_bounds), effective_particles);
+            let solver = ParticleSwarm::new((lower_bounds, upper_bounds), effective_particles)
+                .with_inertia_factor(0.9)
+                .map_err(|e| anyhow::anyhow!("PSO inertia: {e}"))?
+                .with_cognitive_factor(1.5)
+                .map_err(|e| anyhow::anyhow!("PSO cognitive: {e}"))?
+                .with_social_factor(0.8)
+                .map_err(|e| anyhow::anyhow!("PSO social: {e}"))?;
 
             let res = Executor::new(cost_fn, solver)
                 .configure(|state| state.max_iters(max_iters as u64))