TheStreet.com Ratings provides exclusive stock, ETF and mutual fund recommendations using proprietary tools. Our "safety first" approach aims to reduce risk while achieving total return performance.

BOSTON ( TheStreet) -- The following companies have annual revenue above $500 million, below-average valuations, debt that is less than 49% of total capital and receive "buy" ratings from our proprietary quantitative model, which considers more than 60 factors. They're ordered by their potential to appreciate, starting with the company with the best growth prospects.

MGE Energy ( MGEE) is a Wisconsin-based electric utility.

The numbers: Second-quarter net income dropped 6% to $10 million and earnings per share fell 10% to 43 cents, hurt by a higher share count. Revenue decreased 14% to $108 million. Its gross margin rose from 23% to 25% and its operating margin climbed from 15% to 16%. A quick ratio of 0.3 demonstrates weak liquidity. A debt-to-equity ratio of 0.7 is below the industry average, indicating restrained leverage.

The stock: MGE has advanced 8% this year, matching the Dow Jones Industrial Average, but trailing the S&P 500 Index. The stock trades at a price-to-earnings ratio of 15, a discount to the market and utility peers. Shares pay a 4.1% dividend yield.

Casey's General Stores ( CASY) operates convenience stores in the Midwest.

The numbers: Fiscal first-quarter revenue fell 24% to $1.2 billion, but profit grew 54% to $44 million, or 87 cents a share. Its gross margin rose from 13% to 19% and its operating margin jumped from 3% to 6%. The company has less-than-ideal liquidity, evident in its quick ratio of 0.8. But a debt-to-equity ratio of 0.2 indicates modest leverage.

The stock: Casey's is up 35% this year, beating major U.S. indices. The stock trades at a price-to-earnings ratio of 15, a discount to the market and food retail peers. Shares pay a 1.1% dividend yield.

Ball Corp. ( BLL) makes metal and plastic packaging.

The numbers: Second-quarter net income increased 33% to $133 million and earnings per share jumped 37% to $1.40, boosted by a lower share count. Revenue declined 7% to $1.9 billion. Its gross margin rose from 16% to 17% and its operating margin climbed from 9% to 10%. A quick ratio of 0.5 demonstrates weak liquidity. A debt-to-equity ratio of 1.8 indicates excessive leverage.

The stock: Ball Corp. is up 17% this year, beating the Dow and S&P 500. The stock trades at a price-to-earnings ratio of 14, a discount to the market and container peers. Shares pay a 0.8% dividend yield.

Dollar Tree ( DLTR) operates discount variety stores.

The numbers: Second-quarter profit surged 51% to $57 million, or 63 cents a share, as revenue jumped 12% to $1.2 billion. Its gross margin rose from 37% to 38% and its operating margin increased from 6% to 7%. A quick ratio of 0.8 indicates less-than-ideal liquidity. A debt-to-equity ratio of 0.2 reflects fiscal prudence.

The stock: Dollar Tree has advanced 14% this year, in line with the S&P 500. The stock trades at a price-to-earnings ratio of 16, a discount to the market and general merchandise peers. The company doesn't pay dividends.

ManTech ( MANT) is a cyber-warfare specialist, providing services to U.S. government agencies.

The numbers: Second-quarter net income grew 30% to $29 million and earnings per share jumped 29% to 80 cents, restrained by a higher share count. Its gross margin rose from 16% to 18% and its operating margin increased from 8% to 9%. A quick ratio of 1.8 indicates ample liquidity. The company holds minimal debt.

The stock: ManTech has fallen 12% this year, underperforming major U.S. indices. The stock trades at a price-to-earnings ratio of 17, a discount to the market and tech consulting peers. The company doesn't pay dividends.

TheStreet.com Ratings was given an award this year for "Best Stock Selection" among independent research providers by BNY ConvergEx Group. A rating can be viewed for any stock through our screener. Ratings are derived from a variety of fundamental and pricing figures and represent our opinion of risk-adjusted performance. However, the rating doesn't incorporate all factors that can alter a stock's performance.

-- Reported by Jake Lynch in Boston.

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