the company is preparing for a labor strike as soon as tomorrow at a plant in joilet, illinois. managers and retirees will be used to maintain production of parts for construction and mining equipment. the local international association of machinists rejected caterpillar's latest offer. but health insurance provider humana was not place to hide today. earnings came up well short of analyst estimates, earning four cents less than expected. humana is the country's biggest provide of medicare plans. the firm's higher medical costs are on the rise after customers held off on medical treatment during the recession. shares were sickly today, falling 8% as volume more than quadrupled. among the reasons humana cites for higher mw ical claims: leap year, one extra day in february, new requirements due to the health care reform law and servicing more customers. this is humana's lowest price since october. deal of the day website groupon has had a tough go since becoming a public company in november. the firm has been be-set by accounting questions and worries about its financial controls