diff --git a/freqtrade/exchange/exchange.py b/freqtrade/exchange/exchange.py
index e9d0316d2..7cc436430 100644
--- a/freqtrade/exchange/exchange.py
+++ b/freqtrade/exchange/exchange.py
@@ -1058,7 +1058,7 @@ class Exchange:
             ticker_rate = ticker[conf_strategy['price_side']]
             if ticker['last'] and ticker_rate:
                 if side == 'buy' and ticker_rate > ticker['last']:
-                    balance = conf_strategy['ask_last_balance']
+                    balance = conf_strategy.get('ask_last_balance', 0.0)
                     ticker_rate = ticker_rate + balance * (ticker['last'] - ticker_rate)
                 elif side == 'sell' and ticker_rate < ticker['last']:
                     balance = conf_strategy.get('bid_last_balance', 0.0)
diff --git a/tests/exchange/test_exchange.py b/tests/exchange/test_exchange.py
index 691cf3c03..8cb494edb 100644
--- a/tests/exchange/test_exchange.py
+++ b/tests/exchange/test_exchange.py
@@ -1832,6 +1832,7 @@ def test_fetch_l2_order_book_exception(default_conf, mocker, exchange_name):
     ('ask', 20, 19, 10, 0.3, 17),  # Between ask and last
     ('ask', 5, 6, 10, 1.0, 5),  # last bigger than ask
     ('ask', 5, 6, 10, 0.5, 5),  # last bigger than ask
+    ('ask', 20, 19, 10, None, 20),  # ask_last_balance missing
     ('ask', 10, 20, None, 0.5, 10),  # last not available - uses ask
     ('ask', 4, 5, None, 0.5, 4),  # last not available - uses ask
     ('ask', 4, 5, None, 1, 4),  # last not available - uses ask
@@ -1842,6 +1843,7 @@ def test_fetch_l2_order_book_exception(default_conf, mocker, exchange_name):
     ('bid', 21, 20, 10, 0.7, 13),  # Between bid and last
     ('bid', 21, 20, 10, 0.3, 17),  # Between bid and last
     ('bid', 6, 5, 10, 1.0, 5),  # last bigger than bid
+    ('bid', 21, 20, 10, None, 20),  # ask_last_balance missing
     ('bid', 6, 5, 10, 0.5, 5),  # last bigger than bid
     ('bid', 21, 20, None, 0.5, 20),  # last not available - uses bid
     ('bid', 6, 5, None, 0.5, 5),  # last not available - uses bid
@@ -1851,7 +1853,10 @@ def test_fetch_l2_order_book_exception(default_conf, mocker, exchange_name):
 def test_get_buy_rate(mocker, default_conf, caplog, side, ask, bid,
                       last, last_ab, expected) -> None:
     caplog.set_level(logging.DEBUG)
-    default_conf['bid_strategy']['ask_last_balance'] = last_ab
+    if last_ab is None:
+        del default_conf['bid_strategy']['ask_last_balance']
+    else:
+        default_conf['bid_strategy']['ask_last_balance'] = last_ab
     default_conf['bid_strategy']['price_side'] = side
     exchange = get_patched_exchange(mocker, default_conf)
     mocker.patch('freqtrade.exchange.Exchange.fetch_ticker',
@@ -1876,6 +1881,7 @@ def test_get_buy_rate(mocker, default_conf, caplog, side, ask, bid,
     ('bid', 12.0, 11.2, 10.5, 1.0, 11.2),  # Last smaller than bid - uses bid
     ('bid', 12.0, 11.2, 10.5, 0.5, 11.2),  # Last smaller than bid - uses bid
     ('bid', 0.003, 0.002, 0.005, 0.0, 0.002),
+    ('bid', 0.003, 0.002, 0.005, None, 0.002),
     ('ask', 12.0, 11.0, 12.5, 0.0, 12.0),  # full ask side
     ('ask', 12.0, 11.0, 12.5, 1.0, 12.5),  # full last side
     ('ask', 12.0, 11.0, 12.5, 0.5, 12.25),  # between bid and lat
@@ -1886,6 +1892,7 @@ def test_get_buy_rate(mocker, default_conf, caplog, side, ask, bid,
     ('ask', 10.11, 11.2, 11.0, 0.0, 10.11),
     ('ask', 0.001, 0.002, 11.0, 0.0, 0.001),
     ('ask', 0.006, 1.0, 11.0, 0.0, 0.006),
+    ('ask', 0.006, 1.0, 11.0, None, 0.006),
 ])
 def test_get_sell_rate(default_conf, mocker, caplog, side, bid, ask,
                        last, last_ab, expected) -> None: