NEW YORK (

TheStreet

) -- Health care company

Humana

(HUM) - Get Report

was the worst-performing stock in the

S&P 500

on Monday morning.

The S&P 500 was falling 5.75 points, or 0.41%, to 1,397.61.

Shares of Humana fell 6.1% Monday morning to $82.46. The company reported first-quarter earnings of $248 million, or $1.49 a share, down 21% from year-earlier earnings of $315 million, or $1.86 a share. Analysts were expecting earnings of

$1.52 a share

.

Humana also raised its full-year 2012 guidance to a range of between $7.55 a share and $7.75 a share from a previous range of between $7.50 a share and $7.70 a share. Analysts are anticipating earnings of $7.99 a share.

Humana trades at an estimated price-to-earnings ratio for next year of 9.23 times; the average for health care providers is 17.23. For comparison,

WellPoint

(WLP)

has a lower forward P/E of 8.02.

Thirteen of the 21 analysts who cover Humana rated it buy; eight analysts gave the stock a hold rating.

Humana's stock has fallen 5.87% year to date.

-- Written by Alexandra Zendrian

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