高高飞翔

    从3万英尺的高空俯视，今年股市的跌宕起伏看来还不算太坏，标准普尔500指数今年也只跌了3%。

    《财富》美国500强公司的表现处在中游，其中半数公司股价上涨。约30%的公司获得了两位数的涨幅。

    表现最佳的公司包括万事达（MasterCard）；借记卡收费改革没有像最初担心得那么糟糕，令其受益。零售商的状况也不错，消费者开始放松捂紧的钱包。

    以下是2011年《财富》美国500强中涨幅最大的十只股票（从第十名到第一名排列），以12月9日收盘价计算涨幅。

Flying high

    From 30,000 feet, this year's volatile swings in the stock market don't look as bad, with the S&P 500 down only 3% for the year.

    Fortune 500 companies took the middle ground, with half of those companies posting gains. Roughly 30% enjoyed double-digit percentage stock increases.

    Among the best performers were companies like MasterCard, which benefited because a change to debit fee regulation was not as bad as first feared. Retailers also fared well as consumers began to loosen those proverbial purse strings.

    Click through to see the top 10 Fortune 500 performers (counting down from good to great), based on their closing prices as of Dec. 9.

第10名：Centene医疗补助保险公司

    交易代码： CNC

    年初至今股票涨幅：48%

    市值： 18亿美元

    500强排名：493

    Centene提供医疗补助（Medicaid）管理式医疗计划和相关服务。今年它的参保人数持续增加，业务也拓展至佛罗里达州、伊利诺伊州、密西西比州和德克萨斯州等地，公司股价迎来大幅上涨。

    总部位于圣路易斯的Centene在最近一期季报中宣称拥有160万人参保，较一年前增加了近8%。投资者也很高兴看到该公司上调了全年业绩指导值。

    推动Centene股价上扬的因素的还包括收购传闻。几家大型健康保险公司收购了一些专为医疗补助患者服务的中小公司后，据称收购这家管理式医疗计划提供商的时机也已经成熟。

    富国银行（Wells Fargo）的分析师们表示，该公司也可能受益于医疗改革，因为改革将大大放宽医疗补助的参保符合条件。一些现金紧缺的州政府早已开始考虑将医疗补助的参保人群交给承诺控制成本的管理式医疗计划提供商。

#10 Centene

    Ticker: CNC

    YTD stock performance: 48%

    Market cap: $1.8 billion

    Fortune 500 Rank: 493

    Shares of Centene, which provides managed care programs and related services to individuals under Medicaid, surged as the company continued to add more members and expand into new states, including Florida, Illinois, Mississippi and Texas.

    In its last quarterly report, St. Louis-based Centene boasted 1.6 million members, up almost 8% from a year ago. Investors were also pleased that the company raised its outlook for the year.

    Centene's stock has also benefited from talk that the managed-care provider could be ripe for a takeover, following a slew of acquisitions by major health insurers of smaller companies that specialize in covering Medicaid patients.

    Wells Fargo analysts say the company is also likely to benefit from health reform, since it is set to substantially expand Medicaid eligibility. Cash-strapped states have already started looking into shifting recipients to managed-care providers, which have promised to keep costs low.