UPDATE: Oppenheimer Upgrades Athenahealth to Perform

Oppenheimer raises its rating on Athenahealth (NASDAQ: ATHN) as it believes the stock has upside following sell-off after the company posted disappointing guidance on investor day.

Oppenheimer notes, "We expect the shares to settle back in the low-to-mid 40s, as we believe short covering provided support yesterday. However, our Underperform rating was based on 2012 estimates being too high and with management resetting expectations the short catalyst has been removed. While our concerns about rising customer acquisition costs remain, we believe management has established beatable expectations."

ATHN closed at $49.04 per share on Thursday.