What are the main reasons for Humana's fall today ? From news : "....Health insurer Humana Inc. (NYSE:HUM, $43.56, -$1.97, -4.33%) on Monday posted better-than-expected profit during the first quarter, by increased enrollment in its Medicare plans for the elderly and operating cost controls. First-quarter net income increased to $258.77 million or $1.52 per share from $205.72 million or $1.22 per share in the previous year. ...."