diff --git a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/factory.js b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/factory.js
index 6e7eef33833d..d403e5d837bf 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/factory.js
+++ b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/factory.js
@@ -88,16 +88,21 @@ function factory( r, p ) {
 		if ( isnan( k ) || k < 0.0 || k > 1.0 ) {
 			return NaN;
 		}
+		if ( p === 1.0 ) {
+			return 0.0;
+		}
 		if ( k === 0.0 ) {
 			return 0.0;
 		}
 		if ( k === 1.0 ) {
 			return PINF;
 		}
+
 		// If the mean overflows double-precision floating-point format, the sought quantile saturates at positive infinity:
 		if ( mu === PINF ) {
 			return PINF;
 		}
+
 		// Cornish-Fisher expansion:
 		if ( k < 0.5 ) {
 			x = -erfcinv( 2.0 * k ) * SQRT2;
diff --git a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/main.js b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/main.js
index d58c5431f8d9..0de81b47f1c4 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/main.js
+++ b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/lib/main.js
@@ -118,6 +118,9 @@ function quantile( k, r, p ) {
 	) {
 		return NaN;
 	}
+	if ( p === 1.0 ) {
+		return 0.0;
+	}
 	if ( k === 0.0 ) {
 		return 0.0;
 	}
diff --git a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/src/main.c b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/src/main.c
index 1e62a238838d..ac234cdbbe57 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/src/main.c
+++ b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/src/main.c
@@ -106,6 +106,9 @@ double stdlib_base_dists_negative_binomial_quantile( const double k, const doubl
 	) {
 		return 0.0 / 0.0; // NaN
 	}
+	if ( p == 1.0 ) {
+		return 0.0;
+	}
 	if ( k == 0.0 ) {
 		return 0.0;
 	}
diff --git a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.factory.js b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.factory.js
index c9dc483a0232..cf81f6cf3f10 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.factory.js
+++ b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.factory.js
@@ -156,6 +156,21 @@ tape( 'if provided a success probability `p` equal to `0`, the created function
 	t.end();
 });
 
+tape( 'if provided a success probability `p` equal to `1`, the created function always returns `0`', function test( t ) {
+	var quantile;
+	var y;
+
+	quantile = factory( 20.0, 1.0 );
+
+	y = quantile( 0.5 );
+	t.strictEqual( y, 0.0, 'returns expected value' );
+
+	y = quantile( 0.9 );
+	t.strictEqual( y, 0.0, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'if the distribution mean overflows double-precision floating-point format, the created function returns `+infinity`', function test( t ) {
 	var quantile;
 	var y;
diff --git a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.main.js b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.main.js
index 4fd65da45c6d..ef8bb1cd1cde 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.main.js
+++ b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.main.js
@@ -106,6 +106,18 @@ tape( 'if provided a success probability `p` equal to `0`, the function returns
 	t.end();
 });
 
+tape( 'if provided a success probability `p` equal to `1`, the function returns `0`', function test( t ) {
+	var y;
+
+	y = quantile( 0.5, 20, 1.0 );
+	t.strictEqual( y, 0.0, 'returns expected value' );
+
+	y = quantile( 0.9, 10, 1.0 );
+	t.strictEqual( y, 0.0, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'if the distribution mean overflows double-precision floating-point format, the function returns `+infinity`', function test( t ) {
 	var y;
 
diff --git a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.native.js b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.native.js
index 31ce5b92aef5..0a202c12a685 100644
--- a/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.native.js
+++ b/lib/node_modules/@stdlib/stats/base/dists/negative-binomial/quantile/test/test.native.js
@@ -115,6 +115,18 @@ tape( 'if provided a success probability `p` equal to `0`, the function returns
 	t.end();
 });
 
+tape( 'if provided a success probability `p` equal to `1`, the function returns `0`', opts, function test( t ) {
+	var y;
+
+	y = quantile( 0.5, 20, 1.0 );
+	t.strictEqual( y, 0.0, 'returns expected value' );
+
+	y = quantile( 0.9, 10, 1.0 );
+	t.strictEqual( y, 0.0, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'if the distribution mean overflows double-precision floating-point format, the function returns `+infinity`', opts, function test( t ) {
 	var y;