MasterCard (NYSE:MA) grabbed the number one slot in Bloomberg Businessweek’s annual ranking of the 50 top-performing S&P 500 companies, with Priceline.com (NASDAQ:PCLN), American Tower (NYSE:AMT), Dollar Tree (NASDAQ:DLTR) and Union Pacific (NYSE:UNP) filling out the top five.

The Bloomberg Businessweek 50 ranks companies according to their 1-year and 5-year risk-adjusted returns, consensus analyst recommendations and projected earnings growth. The list revealed notable trends: Six companies ascended to the list thanks to the natural gas boom, and discounters like Dollar Tree have flourished among consumer companies.

According to Bloomberg, MasterCard earned its No. 1 spot in the ranking by achieving 66 percent growth in 2011, with analysts forecasting earnings per share to rise 17 percent in 2012.

Here’s how these stocks reacted to the award:

Mastercard Incorporated (NYSE:MA): MA shares recently traded at $338.61, down $2.05, or 0.6%. They have traded in a 52-week range of $230.31 to $384.99. Volume today was 834,887 shares versus a 3-month average volume of 1,069,270 shares. The company’s trailing P/E is 19.02, while trailing earnings are $17.80 per share.

priceline.com Incorporated (NASDAQ:PCLN): PCLN shares recently traded at $519.15, up $0.57, or 0.11%. They have traded in a 52-week range of $411.26 to $561.88. Volume today was 548,522 shares versus a 3-month average volume of 1,053,020 shares. The company’s trailing P/E is 27.50, while trailing earnings are $18.88 per share.

American Tower Corp. (NYSE:AMT): AMT shares recently traded at $61.74, up $0.23, or 0.37%. They have traded in a 52-week range of $45.85 to $62.97. Volume today was 1,634,360 shares versus a 3-month average volume of 3,105,920 shares. The company’s trailing P/E is 89.48, while trailing earnings are $0.69 per share.

Dollar Tree, Inc. (NASDAQ:DLTR): DLTR shares recently traded at $85.77, up $1.31, or 1.55%. They have traded in a 52-week range of $48.51 to $86.50. Volume today was 877,745 shares versus a 3-month average volume of 1,817,050 shares. The company’s trailing P/E is 22.87, while trailing earnings are $3.75 per share.

Union Pacific Corporation (NYSE:UNP): UNP shares recently traded at $111.49, down $1.35, or 1.2%. They have traded in a 52-week range of $77.73 to $114.82. Volume today was 2,037,126 shares versus a 3-month average volume of 2,796,720 shares. The company’s trailing P/E is 16.59, while trailing earnings are $6.72 per share.

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