diff --git a/src/Data/Text/DelimitedReader.cs b/src/Data/Text/DelimitedReader.cs
index 0c5eda59..df99109e 100644
--- a/src/Data/Text/DelimitedReader.cs
+++ b/src/Data/Text/DelimitedReader.cs
@@ -76,7 +76,7 @@ namespace MathNet.Numerics.Data.Text
             where T : struct, IEquatable<T>, IFormattable
         {
             delimiter = CleanDelimiter(delimiter);
-            var mv = missingValue ?? NaN<T>();
+            var mv = missingValue ?? (sparse ? Zero<T>() : NaN<T>());
             var mvStr = mv.ToString("G", formatProvider);
 
             var regex = delimiter == @"\s" ?
@@ -234,6 +234,14 @@ namespace MathNet.Numerics.Data.Text
             throw new NotSupportedException();
         }
 
+        /// <summary>
+        /// Zero for the given numeric type.
+        /// </summary>
+        static T Zero<T>() where T : struct
+        {
+            return default(T);
+        }
+
         static Func<string, T> CreateParser<T>(IFormatProvider formatProvider)
         {
             if (typeof (T) == typeof (double))
diff --git a/src/DataUnitTests/Text/DelimitedReaderTests.cs b/src/DataUnitTests/Text/DelimitedReaderTests.cs
index 59dcad57..3bbc210a 100644
--- a/src/DataUnitTests/Text/DelimitedReaderTests.cs
+++ b/src/DataUnitTests/Text/DelimitedReaderTests.cs
@@ -33,6 +33,7 @@ using System.Globalization;
 using System.IO;
 using System.Numerics;
 using System.Text;
+using MathNet.Numerics.LinearAlgebra.Storage;
 using NUnit.Framework;
 using MathNet.Numerics.Data.Text;
 
@@ -255,7 +256,7 @@ namespace MathNet.Numerics.Data.UnitTests.Text
             Assert.AreEqual(double.NaN, matrix[1, 1]);
             Assert.AreEqual(double.NaN, matrix[1, 2]);
             Assert.AreEqual(3.0, matrix[1, 3]);
-            Assert.AreEqual(double.NaN, matrix[1, 4]); 
+            Assert.AreEqual(double.NaN, matrix[1, 4]);
             Assert.AreEqual(4.0, matrix[2, 0]);
             Assert.AreEqual(0.0, matrix[2, 1]);
             Assert.AreEqual(6.0, matrix[2, 2]);
@@ -265,7 +266,7 @@ namespace MathNet.Numerics.Data.UnitTests.Text
             Assert.AreEqual(double.NaN, matrix[3, 1]);
             Assert.AreEqual(double.NaN, matrix[3, 2]);
             Assert.AreEqual(double.NaN, matrix[3, 3]);
-            Assert.AreEqual(double.NaN, matrix[3, 4]); 
+            Assert.AreEqual(double.NaN, matrix[3, 4]);
             Assert.AreEqual(double.NaN, matrix[4, 0]);
             Assert.AreEqual(double.NaN, matrix[4, 1]);
             Assert.AreEqual(3.0, matrix[4, 2]);
@@ -304,10 +305,11 @@ namespace MathNet.Numerics.Data.UnitTests.Text
                        + "\"2.2\"\\0.3e1" + Environment.NewLine
                        + "'4'\\0\\6" + Environment.NewLine;
 
-            var matrix = DelimitedReader.Read<double>(new StringReader(data), true, "\\", true, CultureInfo.InvariantCulture, missingValue:0.0);
+            var matrix = DelimitedReader.Read<double>(new StringReader(data), true, "\\", true, CultureInfo.InvariantCulture);
             Assert.IsTrue(matrix is LinearAlgebra.Double.SparseMatrix);
             Assert.AreEqual(3, matrix.RowCount);
             Assert.AreEqual(3, matrix.ColumnCount);
+            Assert.AreEqual(5, ((SparseCompressedRowMatrixStorage<double>)matrix.Storage).ValueCount);
             Assert.AreEqual(1.0, matrix[0, 0]);
             Assert.AreEqual(0.0, matrix[0, 1]);
             Assert.AreEqual(0.0, matrix[0, 2]);
@@ -334,6 +336,7 @@ namespace MathNet.Numerics.Data.UnitTests.Text
             Assert.IsTrue(matrix is LinearAlgebra.Double.SparseMatrix);
             Assert.AreEqual(3, matrix.RowCount);
             Assert.AreEqual(3, matrix.ColumnCount);
+            Assert.AreEqual(5, ((SparseCompressedRowMatrixStorage<double>)matrix.Storage).ValueCount);
             Assert.AreEqual(1.0, matrix[0, 0]);
             Assert.AreEqual(0.0, matrix[0, 1]);
             Assert.AreEqual(0.0, matrix[0, 2]);