diff --git a/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.cpp b/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.cpp
index 8efd085c4..82144e3fc 100644
--- a/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.cpp
+++ b/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.cpp
@@ -21,7 +21,7 @@ namespace storm {
             components.choiceLabeling = buildChoiceLabeling(components.transitionMatrix);
             // Now delete unreachable states.
             storm::storage::BitVector allStates(components.transitionMatrix.getRowGroupCount(), true);
-            auto reachableStates = storm::utility::graph::getReachableStates(components.transitionMatrix, components.stateLabeling.getStates("init"), allStates, ~allStates);
+            reachableStates = storm::utility::graph::getReachableStates(components.transitionMatrix, components.stateLabeling.getStates("init"), allStates, ~allStates);
             storm::storage::BitVector enabledActions(components.transitionMatrix.getRowCount());
             for (uint64_t state : reachableStates) {
                 for (uint64_t row = components.transitionMatrix.getRowGroupIndices()[state]; row < components.transitionMatrix.getRowGroupIndices()[state + 1]; ++ row) {
@@ -34,8 +34,7 @@ namespace storm {
 
             // build the remaining components
             for (auto const& rewModel : model.getRewardModels()) {
-                components.rewardModels.emplace(rewModel.first,
-                                                buildRewardModel(rewModel.second, reachableStates, components.transitionMatrix));
+                components.rewardModels.emplace(rewModel.first, buildRewardModel(rewModel.second, reachableStates, components.transitionMatrix));
             }
 
             // build the offset vector, that allows to maintain getter indices
@@ -53,7 +52,7 @@ namespace storm {
             productStates[0] = 0;
             for (uint64_t modelState = 0; modelState < model.getNumberOfStates(); ++ modelState) {
                 if (modelState < model.getNumberOfStates() - 1) {
-                    productStates[modelState + 1] = productStates[modelState] + memory.getNumberOfStates() * ( 1 + origTransitions.getRowGroupEntryCount(modelState) );
+                    productStates[modelState + 1] = productStates[modelState] + memory.getNumberOfStates() * (1 + origTransitions.getRowGroupEntryCount(modelState));
                 }
                 for (uint64_t memState = 0; memState < memory.getNumberOfStates(); ++ memState) {
                     for (uint64_t row = origTransitions.getRowGroupIndices()[modelState];
@@ -307,14 +306,22 @@ namespace storm {
         template<typename SparseModelType>
         std::vector<uint64_t> SparseModelNondeterministicTransitionsBasedMemoryProduct<SparseModelType>::generateOffsetVector(storm::storage::BitVector const& reachableStates) {
             uint64_t numberOfStates = model.getNumberOfStates() * memory.getNumberOfStates() * (1 + model.getNumberOfTransitions());
-            STORM_LOG_ASSERT(reachableStates.size() == numberOfStates, "wrong size for the vector reachableStates");
+            STORM_LOG_ASSERT(reachableStates.size() == numberOfStates, "vector reachableStates has wrong size");
+            uint64_t state = 0;
             uint64_t offset = 0;
             std::vector<uint64_t> offsetVector(numberOfStates);
-            for (uint64_t state = 0; state < numberOfStates; ++ state) {
-                if (not reachableStates[state]) {
-                    ++ offset;
+            while (state < numberOfStates) {
+                if (reachableStates[state]) {
+                    offsetVector[state] = offset;
+                    ++ state;
+                }
+                else {
+                    uint64_t nextState = reachableStates.getNextSetIndex(state);
+                    offset += nextState - state;
+                    for (; state < nextState; ++ state) {
+                        offsetVector[state] = offset;
+                    }
                 }
-                offsetVector[state] = offset;
             }
 
             return std::move(offsetVector);
@@ -328,9 +335,9 @@ namespace storm {
 
         template<typename SparseModelType>
         bool SparseModelNondeterministicTransitionsBasedMemoryProduct<SparseModelType>::isProductStateReachable(uint64_t modelState, uint64_t memoryState) const {
-            STORM_LOG_ASSERT(not fullProductStatesOffset.empty(), "Model not built");
+            STORM_LOG_ASSERT(not fullProductStatesOffset.empty(), "The product is not yet built");
             uint64_t index = productStates[modelState] + memoryState * (1 + model.getTransitionMatrix().getRowGroupEntryCount(modelState));
-            return ( index == 0 and fullProductStatesOffset[index] == 0 ) or ( index > 0 and fullProductStatesOffset[index] == fullProductStatesOffset[index - 1] );
+            return reachableStates[index];
         }
 
         template<typename SparseModelType>
@@ -343,8 +350,10 @@ namespace storm {
 
         template<typename SparseModelType>
         uint64_t SparseModelNondeterministicTransitionsBasedMemoryProduct<SparseModelType>::getMemoryState(uint64_t productState) const {
-            uint64_t modelState = getModelState(productState);
-            uint64_t offset = productState - productStates[modelState];
+            uint64_t productStateWithOffset = productState + (fullProductStatesOffset.empty() ? 0 : fullProductStatesOffset[productState]);
+            // binary search in the vector containing the product states indices
+            uint64_t modelState = std::upper_bound(productStates.begin(), productStates.end(), productStateWithOffset) - productStates.begin() - 1;
+            uint64_t offset = productStateWithOffset - productStates[modelState];
             return offset / (1 + model.getTransitionMatrix().getRowGroupEntryCount(modelState));
         }
 
diff --git a/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.h b/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.h
index 1f4ab9270..97384d9ef 100644
--- a/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.h
+++ b/src/storm/storage/memorystructure/SparseModelNondeterministicTransitionsBasedMemoryProduct.h
@@ -45,6 +45,7 @@ namespace storm {
             storm::storage::NondeterministicMemoryStructure const& memory;
             std::vector<uint64_t> productStates; // has a size equals to the number of states of the original model
             std::vector<uint64_t> fullProductStatesOffset; // has a size equal to the number of states of the full product
+            storm::storage::BitVector reachableStates;
             bool forceLabeling;
         };