October. This is one of the peculiarly dangerous months to speculate in stocks in. The others are July, January, September, April, November, May, March, June, December, August, and February.
Source: Pudd'nhead Wilson, ch. 13, Pudd'nhead Wilson's Calendar, 1894.
-- Mark Twain, (Nov 30 1835-1910), US novelist, journalist, river pilot; The Great American humorist was also known as The People's Author and creator of Tom Sawyer and Huck Finn.