diff --git a/finquant/monte_carlo.py b/finquant/monte_carlo.py
index 2a9576d2..e741f666 100644
--- a/finquant/monte_carlo.py
+++ b/finquant/monte_carlo.py
@@ -34,7 +34,7 @@ def run(self, fun, **kwargs):
         for i in range(self.num_trials):
             res = fun(**kwargs)
             result.append(res)
-        return np.asarray(result)
+        return np.asarray(result, dtype=object)
 
 
 class MonteCarloOpt(MonteCarlo):