diff --git a/src/finam/data/tools.py b/src/finam/data/tools.py
index 08273bd0a64549a1c678cebdde6fb982cef27d51..b5c243aed9aba397cc7d15ddc23d078ba9f5ae33 100644
--- a/src/finam/data/tools.py
+++ b/src/finam/data/tools.py
@@ -66,14 +66,6 @@ def prepare(data, info, time_entries=1, force_copy=False, report_conversion=Fals
                 f"Given data has incompatible units. "
                 f"Got {data.units}, expected {units}."
             )
-        if not isinstance(data.magnitude, np.ndarray):
-            if force_copy:
-                data = copy.copy(data.magnitude)
-            else:
-                data = data.magnitude
-
-            data = UNITS.Quantity(np.asarray(data), data.units)
-
         if not equivalent_units(data.units, units):
             units_converted = data.units, units
             data = data.to(units)
diff --git a/tests/data/test_tools.py b/tests/data/test_tools.py
index e9bf06633cddd59cc85099ce03325af4ea932dee..7443778bcbfdc5167e83967e0e633158e5f4b88c 100644
--- a/tests/data/test_tools.py
+++ b/tests/data/test_tools.py
@@ -134,6 +134,14 @@ class TestDataTools(unittest.TestCase):
         )
         self.assertEqual((1, 2, 2), data.shape)
 
+        data = finam.data.prepare(
+            finam.UNITS.Quantity(1.0, "m"),
+            finam.Info(time, grid=finam.NoGrid(), units="m"),
+        )
+
+        self.assertEqual((1,), data.shape)
+        self.assertEqual(finam.UNITS.meter, data.units)
+
         with self.assertRaises(finam.errors.FinamDataError):
             finam.data.prepare(
                 np.asarray([1, 2]), finam.Info(time, grid=finam.NoGrid())
@@ -192,6 +200,13 @@ class TestDataTools(unittest.TestCase):
         xdata[0, 0] = 0 * finam.UNITS("m")
         self.assertNotEqual(finam.data.get_magnitude(xdata2[0, 0]), 0.0)
 
+        data = [1.0]
+        xdata2 = finam.data.prepare(data, info_1, force_copy=True)
+        self.assertEqual(1.0 * finam.UNITS.meter, xdata2[0])
+
+        xdata2[0, 0] = 0 * finam.UNITS("m")
+        self.assertNotEqual(0.0, data[0])
+
     def test_assert_type(self):
         finam.data.assert_type(self, "A", 1, [int, float])