First Week of August 21st Options Trading For Houghton Mifflin Harcourt (HMHC) By: Market News Video June 25, 2015 at 10:50 AM EDT Investors in Houghton Mifflin Harcourt Co. (HMHC) saw new options begin trading this week, for the August 21st expiration.. Read More >> Related Stocks: Houghton Mifflin Har