diff --git a/gym_anytrading/envs/trading_env.py b/gym_anytrading/envs/trading_env.py
index 8e2aa56..e12bd88 100644
--- a/gym_anytrading/envs/trading_env.py
+++ b/gym_anytrading/envs/trading_env.py
@@ -102,7 +102,7 @@ def step(self, action):
 
 
     def _get_observation(self):
-        return self.signal_features[(self._current_tick-self.window_size):self._current_tick]
+        return self.signal_features[(self._current_tick-self.window_size+1):self._current_tick+1]
 
 
     def _update_history(self, info):