diff --git a/Eigen/src/SparseCore/SparseMatrix.h b/Eigen/src/SparseCore/SparseMatrix.h
index 8d57cbcf1..b7f437ede 100644
--- a/Eigen/src/SparseCore/SparseMatrix.h
+++ b/Eigen/src/SparseCore/SparseMatrix.h
@@ -694,6 +694,11 @@ class SparseMatrix
       Base::operator=(other);
     }
 
+    inline SparseMatrix(SparseMatrix&& other) : Base(), m_outerSize(0), m_innerSize(0), m_outerIndex(0), m_innerNonZeros(0)
+    {
+      *this = other.derived().markAsRValue();
+    }
+
     /** Copy constructor (it performs a deep copy) */
     inline SparseMatrix(const SparseMatrix& other)
       : Base(), m_outerSize(0), m_innerSize(0), m_outerIndex(0), m_innerNonZeros(0)
@@ -742,6 +747,7 @@ class SparseMatrix
       internal::conditional_aligned_delete_auto<StorageIndex, true>(m_innerNonZeros, m_outerSize);
       m_innerNonZeros = 0;
     }
+
     inline SparseMatrix& operator=(const SparseMatrix& other)
     {
       if (other.isRValue())
@@ -767,6 +773,10 @@ class SparseMatrix
       return *this;
     }
 
+    inline SparseMatrix& operator=(SparseMatrix&& other) {
+      return *this = other.derived().markAsRValue();
+    }
+
 #ifndef EIGEN_PARSED_BY_DOXYGEN
     template<typename OtherDerived>
     inline SparseMatrix& operator=(const EigenBase<OtherDerived>& other)
@@ -1497,8 +1507,8 @@ struct evaluator<SparseMatrix<Scalar_,Options_,StorageIndex_> >
 }
 
 // Specialization for SparseMatrix.
-// Serializes [rows, cols, isCompressed, outerSize, numNonZeros, innerNonZeros,
-// outerIndices, innerIndices, values].
+// Serializes [rows, cols, isCompressed, outerSize, innerBufferSize,
+// innerNonZeros, outerIndices, innerIndices, values].
 template <typename Scalar, int Options, typename StorageIndex>
 class Serializer<SparseMatrix<Scalar, Options, StorageIndex>, void> {
  public:
@@ -1509,19 +1519,19 @@ class Serializer<SparseMatrix<Scalar, Options, StorageIndex>, void> {
     typename SparseMat::Index cols;
     bool compressed;
     Index outer_size;
-    Index num_non_zeros;
+    Index inner_buffer_size;
   };
 
   EIGEN_DEVICE_FUNC size_t size(const SparseMat& value) const {
     // innerNonZeros.
-    std::size_t num_storage_indices =
-        value.isCompressed() ? 0 : value.outerSize();
+    std::size_t num_storage_indices = value.isCompressed() ? 0 : value.outerSize();
     // Outer indices.
     num_storage_indices += value.outerSize() + 1;
     // Inner indices.
-    num_storage_indices += value.nonZeros();
+    const StorageIndex inner_buffer_size = value.outerIndexPtr()[value.outerSize()];
+    num_storage_indices += inner_buffer_size;
     // Values.
-    std::size_t num_values = value.nonZeros();
+    std::size_t num_values = inner_buffer_size;
     return sizeof(Header) + sizeof(Scalar) * num_values +
            sizeof(StorageIndex) * num_storage_indices;
   }
@@ -1533,30 +1543,30 @@ class Serializer<SparseMatrix<Scalar, Options, StorageIndex>, void> {
 
     const size_t header_bytes = sizeof(Header);
     Header header = {value.rows(), value.cols(), value.isCompressed(),
-                     value.outerSize(), value.nonZeros()};
+                     value.outerSize(), value.outerIndexPtr()[value.outerSize()]};
     EIGEN_USING_STD(memcpy)
     memcpy(dest, &header, header_bytes);
     dest += header_bytes;
 
     // innerNonZeros.
-    size_t data_bytes = sizeof(StorageIndex) * header.outer_size;
     if (!header.compressed) {
+      std:size_t data_bytes = sizeof(StorageIndex) * header.outer_size;
       memcpy(dest, value.innerNonZeroPtr(), data_bytes);
       dest += data_bytes;
     }
 
     // Outer indices.
-    data_bytes = sizeof(StorageIndex) * (header.outer_size + 1);
+    std::size_t data_bytes = sizeof(StorageIndex) * (header.outer_size + 1);
     memcpy(dest, value.outerIndexPtr(), data_bytes);
     dest += data_bytes;
 
     // Inner indices.
-    data_bytes = sizeof(StorageIndex) * header.num_non_zeros;
+    data_bytes = sizeof(StorageIndex) * header.inner_buffer_size;
     memcpy(dest, value.innerIndexPtr(), data_bytes);
     dest += data_bytes;
 
     // Values.
-    data_bytes = sizeof(Scalar) * header.num_non_zeros;
+    data_bytes = sizeof(Scalar) * header.inner_buffer_size;
     memcpy(dest, value.valuePtr(), data_bytes);
     dest += data_bytes;
 
@@ -1577,37 +1587,38 @@ class Serializer<SparseMatrix<Scalar, Options, StorageIndex>, void> {
 
     value.setZero();
     value.resize(header.rows, header.cols);
-
-    // Initialize compressed state and inner non-zeros.
-    size_t data_bytes = sizeof(StorageIndex) * header.outer_size;
-    if (EIGEN_PREDICT_FALSE(src + data_bytes > end)) return nullptr;
     if (header.compressed) {
       value.makeCompressed();
-      value.resizeNonZeros(header.num_non_zeros);
     } else {
-      // Temporarily load inner sizes, then reserve.
-      std::vector<StorageIndex> inner_sizes(header.outer_size);
-      memcpy(inner_sizes.data(), src, data_bytes);
-      src += data_bytes;
-
       value.uncompress();
-      value.reserve(inner_sizes);
-      memcpy(value.innerNonZeroPtr(), inner_sizes.data(), data_bytes);
+    }
+    
+    // Adjust value ptr size.
+    value.data().resize(header.inner_buffer_size);
+
+    // Initialize compressed state and inner non-zeros.
+    if (!header.compressed) {           
+      // Inner non-zero counts.
+      std::size_t data_bytes = sizeof(StorageIndex) * header.outer_size;
+      if (EIGEN_PREDICT_FALSE(src + data_bytes > end)) return nullptr;
+      memcpy(value.innerNonZeroPtr(), src, data_bytes);
+      src += data_bytes;
     }
 
     // Outer indices.
-    data_bytes = sizeof(StorageIndex) * (header.outer_size + 1);
+    std::size_t data_bytes = sizeof(StorageIndex) * (header.outer_size + 1);
+    if (EIGEN_PREDICT_FALSE(src + data_bytes > end)) return nullptr;
     memcpy(value.outerIndexPtr(), src, data_bytes);
     src += data_bytes;
 
     // Inner indices.
-    data_bytes = sizeof(StorageIndex) * header.num_non_zeros;
+    data_bytes = sizeof(StorageIndex) * header.inner_buffer_size;
     if (EIGEN_PREDICT_FALSE(src + data_bytes > end)) return nullptr;
     memcpy(value.innerIndexPtr(), src, data_bytes);
     src += data_bytes;
 
     // Values.
-    data_bytes = sizeof(Scalar) * header.num_non_zeros;
+    data_bytes = sizeof(Scalar) * header.inner_buffer_size;
     if (EIGEN_PREDICT_FALSE(src + data_bytes > end)) return nullptr;
     memcpy(value.valuePtr(), src, data_bytes);
     src += data_bytes;
diff --git a/test/serializer.cpp b/test/serializer.cpp
index b48301310..d3e7ba5b2 100644
--- a/test/serializer.cpp
+++ b/test/serializer.cpp
@@ -30,7 +30,7 @@ struct RandomImpl<Eigen::SparseMatrix<Scalar, Options, DenseIndex>> {
     double density = 0.1;
 
     // Reserve some space along each inner dim.
-    int nnz = static_cast<int>(density * 1.5 * M.innerSize());
+    int nnz = static_cast<int>(std::ceil(density * 1.5 * M.innerSize()));
     M.reserve(Eigen::VectorXi::Constant(M.outerSize(), nnz));
 
     for (int j = 0; j < M.outerSize(); j++) {