diff --git a/asset.py b/asset.py
index 148585e..485a4f0 100644
--- a/asset.py
+++ b/asset.py
@@ -8,6 +8,8 @@ from trytond.transaction import Transaction
 from trytond.pool import Pool
 from trytond.pyson import Eval, Bool, And, If, Date
 from trytond.report import Report
+from trytond.cache import Cache
+
 from decimal import Decimal
 from datetime import time
 from sql.functions import CurrentDate, CurrentTimestamp, Round, Extract
@@ -118,6 +120,8 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
         readonly=True, model_name='investment.rate'),
         'get_rate_data')
 
+    _asset_cache = Cache('investment.asset.values', duration=6*3600, context=False)
+
     @classmethod
     def __register__(cls, module_name):
         """ register and migrate
@@ -160,6 +164,17 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                 AssetSourceRel.create(to_create)
             asset_table.drop_column('updtsource')
 
+    @classmethod
+    def values_cache_clear(cls, id_assets, names):
+        """ set cache-values to None
+        """
+        for fname in names:
+            for id1 in id_assets:
+                cls._asset_cache.set('%(fname)s-%(id)d' % {
+                    'fname': fname,
+                    'id': id1,
+                    }, None)
+
     @classmethod
     def view_attributes(cls):
         return super().view_attributes() + [
@@ -550,8 +565,24 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
 
         result = {x:{y.id: None for y in assets} for x in names}
         exp = Decimal(Decimal(1) / 10 ** digits_percent)
+        asset_id_lst = [x.id for x in assets]
 
         for x in names:
+            # try to get values from cache
+            ids_todo = []
+            for id1 in asset_id_lst:
+                c_val = cls._asset_cache.get('%(fname)s-%(id)d' % {
+                    'fname': x,
+                    'id': id1,
+                    })
+                if c_val is None:
+                    ids_todo.append(id1)
+                else :
+                    result[x][id1] = c_val
+
+            if len(ids_todo) == 0:
+                continue
+
             tab_percent = cls.get_percentage_sql(
                 days={
                     'change_day1': 0,
@@ -560,7 +591,7 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
                     'change_month6': 180,
                     'change_month12': 365,
                     }[x],
-                asset_ids=[x.id for x in assets]
+                asset_ids=ids_todo
                 )
             cursor.execute(*tab_percent)
             records = cursor.fetchall()
@@ -568,6 +599,10 @@ class Asset(SymbolMixin, ModelSQL, ModelView):
             for record in records:
                 result[x][record[0]] = record[3].quantize(exp) \
                         if record[3] is not None else None
+                cls._asset_cache.set('%(fname)s-%(id)d' % {
+                    'fname': x,
+                    'id': record[0],
+                    }, result[x][record[0]])
         return result
 
     @classmethod
diff --git a/import_wiz.py b/import_wiz.py
index 84b4dd8..e91ddef 100644
--- a/import_wiz.py
+++ b/import_wiz.py
@@ -201,16 +201,6 @@ class ImportWizard(Wizard):
                         'investment.msg_err_unknown_content',
                         linetxt = line,
                         ))
-
-        # ~ print('- found %d records' % len(result))
-        # ~ print('- dates from %s to %s' % (
-                # ~ min_date.isoformat() if min_date is not None else '-',
-                # ~ max_date.isoformat() if max_date is not None else '-',
-                # ~ ))
-        # ~ print('- rates from %s to %s' % (
-                # ~ str(min_rate) if min_rate is not None else '-',
-                # ~ str(max_rate) if max_rate is not None else '-',
-                # ~ ))
         return (result, max_date, min_date)
 
 # end ImportWizard
diff --git a/rate.py b/rate.py
index e59839b..a8d10d0 100644
--- a/rate.py
+++ b/rate.py
@@ -87,4 +87,34 @@ class Rate(SymbolMixin, ModelSQL, ModelView):
                 result[n][record[0]] = r1[n]
         return result
 
+    @classmethod
+    def create(cls, vlist):
+        """ clear cache
+        """
+        Asset = Pool().get('investment.asset')
+
+        Asset.values_cache_clear(
+            [x['asset'] for x in vlist],
+            ['change_day1', 'change_month1', 'change_month3',
+                'change_month6', 'change_month12'],
+            )
+        return super(Rate, cls).create(vlist)
+
+    @classmethod
+    def write(cls, *args):
+        """ clear cache
+        """
+        Asset = Pool().get('investment.asset')
+
+        asset_ids = []
+        actions = iter(args)
+        for rates, values in zip(actions, actions):
+            asset_ids.extend([x.asset.id for x in rates])
+
+        if len(asset_ids) > 0:
+            Asset.values_cache_clear(asset_ids,
+                ['change_day1', 'change_month1', 'change_month3',
+                    'change_month6', 'change_month12'])
+        super(Rate, cls).write(*args)
+
 # Rate