TheStreet.com Ratings provides exclusive stock, ETF and mutual fund ratings and commentary based on award-winning, proprietary tools. Its "safety first" approach to investing aims to reduce risk while seeking outperformance on a total return basis.TheStreet.com's stock-rating model upgraded CACI ( CACI) to "buy." The company provides information systems and technology services to the U.S. government. The numbers: Fiscal third-quarter revenue increased 4% to $674 million as net income and earnings per share climbed 5% to $23 million and 77 cents, respectively. Operating margin stood at 7% and net margin hovered at 4% despite recessionary pressures. The company has more than tripled its cash reserves to $174 million since the year-earlier quarter and a quick ratio of 2.2 indicates strong liquidity. A debt-to-equity ratio of 0.7 reflects conservative leverage. The stock: CACI has increased 11% in 2009, outperforming the Dow Jones Industrial Average and S&P 500. The stock trades at a fair price-to-earnings ratio of 15, but doesn't pay dividends. The model upgraded Heartland Express ( HTLD) to "buy." The company operates as a short- to medium-haul truckload carrier in the U.S. The numbers: Second-quarter revenue fell 29% to $117 million as net income increased 2% to $18 million and earnings per share climbed 6% to 19 cents, helped by a lower share count. Operating margin climbed from 13% to 15% and net margin jumped from 10% to 15%. The cash balance has increased 59% to $45 million since the year-earlier quarter as the debt load remained at zero. Heartland's quick ratio of 0.8 indicates less-than-ideal liquidity. Our model prefers companies with quick ratios over 1. The stock: Heartland Express has dropped 5% in 2009, underperforming the Dow and S&P 500. The stock trades at an expensive price-to-earnings ratio of 20 and offers a dividend yield below 1%.