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) -- These companies have annual revenue above $500 million, below-average valuations, debt that's less than 49% of total capital and "buy" ratings from our proprietary quantitative model, which considers more than 60 factors. They're ordered by their potential to gain. MGE Energy ( MGEE) is a Wisconsin-based electric company. The numbers: First-quarter revenue dropped 5% to $181 million, but net income increased 8% to $15 million. Earnings per share climbed 3% to 65 cents, hurt by a higher share count. The operating margin passed 13% and the net margin increased from 7% to 8%. Although a quick ratio of 0.4 indicates weak liquidity, MGE has a lower debt load than its peers. A debt-to-equity ratio of 0.8 is a sign of restrained leverage. We give the company a financial strength score of 8.9 out of 10, which is higher than our "buy"-rated average. The stock: MGE has risen 9% this year, beating the Dow Jones Industrial Average, but underperforming the S&P 500 Index. The stock trades at a fair price-to-earnings ratio of 15 and offers a 4% dividend yield, which is higher than the S&P 500 average. Advance Auto Parts ( AAP) sells replacement parts, accessories and maintenance items for cars. The numbers: First-quarter revenue increased 10% to $1.7 billion. Earnings rose 14% to $94 million, or 98 cents. The operating margin remained stable at 9% and the net margin improved from 5% to 6%. Just $51 million of cash reserves and a quick ratio of 0.1 indicate a weak liquidity position. But a debt-to-equity ratio of 0.3 demonstrates modest leverage.