diff -Nuar a/vendor/magento/module-negotiable-quote/Model/NegotiableQuoteConverter.php b/vendor/magento/module-negotiable-quote/Model/NegotiableQuoteConverter.php
index 050f3f6d4..f2ffa7b83 100644
--- a/vendor/magento/module-negotiable-quote/Model/NegotiableQuoteConverter.php
+++ b/vendor/magento/module-negotiable-quote/Model/NegotiableQuoteConverter.php
@@ -6,6 +6,7 @@
 
 namespace Magento\NegotiableQuote\Model;
 
+use Magento\Framework\DataObject;
 use Magento\Quote\Api\Data\CartInterface;
 use Magento\Quote\Api\Data\CartInterfaceFactory;
 use Magento\Catalog\Api\Data\ProductInterfaceFactory;
@@ -20,51 +21,53 @@ use Magento\Quote\Model\ResourceModel\Quote\Item\Collection;
 
 /**
  * Class for convert form negotiable quote to snapshot and vice versa.
+ *
+ * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class NegotiableQuoteConverter
 {
     /**
-     * @var \Magento\Quote\Api\Data\CartInterfaceFactory
+     * @var CartInterfaceFactory
      */
     protected $cartFactory;
 
     /**
-     * @var \Magento\Catalog\Api\Data\ProductInterfaceFactory
+     * @var ProductInterfaceFactory
      */
     protected $productFactory;
 
     /**
-     * @var \Magento\Catalog\Api\ProductRepositoryInterface
+     * @var ProductRepositoryInterface
      */
     protected $productRepository;
 
     /**
-     * @var \Magento\Framework\Api\ExtensionAttributesFactory
+     * @var ExtensionAttributesFactory
      */
     protected $extensionFactory;
 
     /**
-     * @var \Magento\Quote\Api\Data\CartItemInterfaceFactory
+     * @var CartItemInterfaceFactory
      */
     protected $cartItemFactory;
 
     /**
-     * @var \Magento\NegotiableQuote\Api\Data\NegotiableQuoteItemInterfaceFactory
+     * @var NegotiableQuoteItemInterfaceFactory
      */
     protected $negotiableQuoteItemFactory;
 
     /**
-     * @var \Magento\NegotiableQuote\Api\Data\NegotiableQuoteInterfaceFactory
+     * @var NegotiableQuoteInterfaceFactory
      */
     protected $negotiableQuoteFactory;
 
     /**
-     * @var \Magento\Framework\Api\SearchCriteriaBuilder
+     * @var SearchCriteriaBuilder
      */
     protected $searchCriteriaBuilder;
 
     /**
-     * @var \Magento\Framework\Api\FilterBuilder
+     * @var FilterBuilder
      */
     protected $filterBuilder;
 
@@ -169,6 +172,7 @@ class NegotiableQuoteConverter
 
     /**
      * Detect relations between parent and child and set those relations
+     *
      * This will need, to detect in future what items to show and what to hide
      *
      * @param Collection $itemsCollection
@@ -233,7 +237,7 @@ class NegotiableQuoteConverter
                 $productObject = $this->productFactory->create();
                 $productObject->setData($option['product']);
                 $option['product'] = $productObject;
-                $itemObject->addOption(new \Magento\Framework\DataObject($option));
+                $itemObject->addOption(new DataObject($option));
             }
 
             $negotiableQuoteItem = $this->negotiableQuoteItemFactory->create();
diff -Nuar a/vendor/magento/module-negotiable-quote/Ui/DataProvider/DataProvider.php b/vendor/magento/module-negotiable-quote/Ui/DataProvider/DataProvider.php
index 440a1742b..79961e240 100644
--- a/vendor/magento/module-negotiable-quote/Ui/DataProvider/DataProvider.php
+++ b/vendor/magento/module-negotiable-quote/Ui/DataProvider/DataProvider.php
@@ -5,52 +5,59 @@
  */
 namespace Magento\NegotiableQuote\Ui\DataProvider;
 
+use Magento\Authorization\Model\UserContextInterface;
+use Magento\Company\Api\AuthorizationInterface;
+use Magento\Company\Model\Company\Structure;
+use Magento\Framework\Api\ExtensibleDataInterface;
 use Magento\Framework\Api\FilterBuilder;
 use Magento\Framework\Api\Search\SearchCriteriaBuilder;
+use Magento\Framework\App\RequestInterface;
 use Magento\Framework\View\Element\UiComponent\DataProvider\Reporting;
 use Magento\Framework\Api\SearchResultsInterface;
 use Magento\NegotiableQuote\Model\NegotiableQuote;
+use Magento\NegotiableQuote\Model\NegotiableQuoteRepository;
 use Magento\NegotiableQuote\Model\Quote\Address;
+use Magento\Store\Model\StoreManagerInterface;
 
 /**
- * Class DataProvider
+ * Class to provide Negotiable quote list
  *
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvider\DataProvider
 {
     /**
-     * @var \Magento\NegotiableQuote\Model\Quote\Address
+     * @var Address
      */
     private $negotiableQuoteAddress;
 
     /**
-     * @var \Magento\NegotiableQuote\Model\NegotiableQuoteRepository
+     * @var NegotiableQuoteRepository
      */
     private $negotiableQuoteRepository;
 
     /**
-     * @var \Magento\Authorization\Model\UserContextInterface
+     * @var UserContextInterface
      */
     private $userContext;
 
     /**
-     * @var \Magento\Store\Model\StoreManagerInterface
+     * @var StoreManagerInterface
      */
     private $storeManager;
 
     /**
-     * @var \Magento\Company\Model\Company\Structure
+     * @var Structure
      */
     private $structure;
 
     /**
-     * @var \Magento\Framework\App\RequestInterface
+     * @var RequestInterface
      */
     protected $request;
 
     /**
-     * @var \Magento\Company\Api\AuthorizationInterface
+     * @var AuthorizationInterface
      */
     private $authorization;
 
@@ -60,14 +67,14 @@ class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvi
      * @param string $requestFieldName
      * @param Reporting $reporting
      * @param SearchCriteriaBuilder $searchCriteriaBuilder
-     * @param \Magento\Framework\App\RequestInterface $request
+     * @param RequestInterface $request
      * @param FilterBuilder $filterBuilder
-     * @param \Magento\NegotiableQuote\Model\NegotiableQuoteRepository $negotiableQuoteRepository
-     * @param \Magento\Authorization\Model\UserContextInterface $userContext
+     * @param NegotiableQuoteRepository $negotiableQuoteRepository
+     * @param UserContextInterface $userContext
      * @param Address $negotiableQuoteAddress
-     * @param \Magento\Store\Model\StoreManagerInterface $storeManager
-     * @param \Magento\Company\Model\Company\Structure $structure
-     * @param \Magento\Company\Api\AuthorizationInterface $authorization
+     * @param StoreManagerInterface $storeManager
+     * @param Structure $structure
+     * @param AuthorizationInterface $authorization
      * @param array $meta
      * @param array $data
      * @SuppressWarnings(PHPMD.ExcessiveParameterList)
@@ -78,14 +85,14 @@ class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvi
         $requestFieldName,
         Reporting $reporting,
         SearchCriteriaBuilder $searchCriteriaBuilder,
-        \Magento\Framework\App\RequestInterface $request,
+        RequestInterface $request,
         FilterBuilder $filterBuilder,
-        \Magento\NegotiableQuote\Model\NegotiableQuoteRepository $negotiableQuoteRepository,
-        \Magento\Authorization\Model\UserContextInterface $userContext,
+        NegotiableQuoteRepository $negotiableQuoteRepository,
+        UserContextInterface $userContext,
         Address $negotiableQuoteAddress,
-        \Magento\Store\Model\StoreManagerInterface $storeManager,
-        \Magento\Company\Model\Company\Structure $structure,
-        \Magento\Company\Api\AuthorizationInterface $authorization,
+        StoreManagerInterface $storeManager,
+        Structure $structure,
+        AuthorizationInterface $authorization,
         array $meta = [],
         array $data = []
     ) {
@@ -110,15 +117,23 @@ class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvi
     }
 
     /**
-     * {@inheritdoc}
+     * @inheritdoc
      */
     public function getData()
     {
+        /**
+         * Return empty data in the main request.
+         * The quote list will be loaded by custom ajax request.
+         * It prevents double loading of the quote list
+         */
+        if ($this->request->getParam('namespace') === null) {
+            return $this->formatEmptyOutput();
+        }
         return $this->formatOutput($this->getSearchResult());
     }
 
     /**
-     * Returns Search result.
+     * Returns Search result
      *
      * @return SearchResultsInterface
      */
@@ -150,6 +165,8 @@ class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvi
     }
 
     /**
+     * Retrieve customer id
+     *
      * @return int|null
      */
     private function getCustomerId()
@@ -158,6 +175,8 @@ class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvi
     }
 
     /**
+     * Get formatted output result
+     *
      * @param SearchResultsInterface $searchResult
      * @return array
      */
@@ -180,11 +199,13 @@ class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvi
     }
 
     /**
-     * @param \Magento\Framework\Api\ExtensibleDataInterface $item
+     * Add extension attributes to the item
+     *
+     * @param ExtensibleDataInterface $item
      * @param array $itemData
      * @return array
      */
-    private function addExtensionAttributes(\Magento\Framework\Api\ExtensibleDataInterface $item, $itemData = [])
+    private function addExtensionAttributes(ExtensibleDataInterface $item, $itemData = [])
     {
         $extensionAttributes = $item->getExtensionAttributes();
         if (!is_object($extensionAttributes)) {
@@ -202,4 +223,12 @@ class DataProvider extends \Magento\Framework\View\Element\UiComponent\DataProvi
 
         return $itemData;
     }
+
+    private function formatEmptyOutput(): array
+    {
+        return [
+            'totalRecords' => 0,
+            'items' => [],
+        ];
+    }
 }