diff --git a/demo/form_graph.py b/demo/form_graph.py
index a9ba3c8d35..6d6666a9d7 100644
--- a/demo/form_graph.py
+++ b/demo/form_graph.py
@@ -18,6 +18,7 @@ def plot_forecast(final_year, companies, noise, show_legend, point_style):
         ax.plot(x, series, plt_format)
     if show_legend:
         plt.legend(companies)
+    plt.close()
     return fig
 
 
diff --git a/demo/stock_forecast.py b/demo/stock_forecast.py
index 8ea7de9c46..55403bb3c3 100644
--- a/demo/stock_forecast.py
+++ b/demo/stock_forecast.py
@@ -19,6 +19,7 @@ def stock_forecast(final_year, companies, noise, show_legend, point_style):
         ax.plot(x, series, plt_format)
     if show_legend:
         plt.legend(companies)
+    plt.close()
     return fig