TSC 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 solid outperformance on a total return basis.

TheStreet.com Ratings' model downgraded Blackstone Group ( BX) to "sell." The private-equity firm offers funds that invest in companies, real estate and hedge funds.

The numbers: First-quarter revenue fell 31% from a year earlier to $47 million as the company swung to a net loss of $231 million or 84 cents per share. Margins remained negative, but Blackstone's net loss declined from the fourth quarter. The cash balance improved 6.7% over last year's first quarter and the company reduced its debt burden 95% to $83 million.

The stock: Blackstone is up 34% this year after falling 70% in 2008. The stock offers a huge 13.7% dividend yield and management is confident about its ability to achieve a full payout in 2009.

The model downgraded BOK Financial ( BOKF) to "hold." The company provides money management and banking services.

The numbers: First-quarter revenue fell 9.7% to $358 million as net income and earnings per share declined 12% to $55 million and 81 cents, respectively. Operating margin improved 194 basis points to 36% and net margin fell 35 basis points to 15%. The company has $715 million of cash reserves, but a hefty $4.9 billion debt burden.

The stock: BOK Financial shares are down 12% this year, underperforming the Dow Jones Industrial Average and the S&P 500 Index. The stock has a price-to-earnings ratio of 16 and offers a 2.7% dividend yield.

The model upgraded Harbin Electric ( HRBN) to "buy." The company designs and produces electric motors in countries including China.

The numbers: First-quarter revenue climbed 37% to $30 million as net income increased 62% to $8.7 million and earnings per share improved 44% to 39 cents. Its operating margin shrank 12 percentage points to 26% and net margin declined 4 percentage points to 24%. The company has a low debt-to-equity ratio of 0.21 and a high quick ratio of 4.23, indicating ample liquidity.

The stock: Harbin Electric shares have surged 86% in 2009, outperforming all major U.S. indexes. The stock still trades at a low price-to-earnings ratio of 12, but doesn't pay dividends.

The model upgraded Louisiana Bancorp ( LABC) to "buy." This savings and loan company provides banking services in southern Louisiana.

The numbers: First-quarter revenue increased 14% to $4.5 million as net income increased 19% to $740,000 and earnings per share climbed 36% to 15 cents. Operating margin declined 94 basis points to 31% and net margin jumped 74 basis points to 17%. The company has a strong cash position, with $14 million of reserves compared with $64 million of debt. A debt-to-equity ratio of 0.79 indicates conservative leverage.

The stock: Louisiana Bancorp is up 4% in 2009, outperforming the Dow Jones Industrial Average and the S&P 500. The stock trades at a high price-to-earnings ratio of 25 and doesn't pay dividends.

The model upgraded NRG Energy ( NRG) to "buy." The company sells power it generates from natural gas, coal, wind and nuclear plants.

The numbers: First-quarter revenue increased 27% to $1.7 billion as net income quadrupled to $198 million and earnings per share surged 483% to 70 cents. Operating margin increased by 18 percentage points to 38% and net margin climbed 8 percentage points to 12%. The company's cash balance has almost tripled to $2.5 billion from a year earlier, but the firm still has a weak quick ratio of 0.5. The debt-to-equity ratio is higher-than-ideal at 1.03, but heavy debt is a common problem for utilities.

The stock: NRG Energy has gained 2% in 2009, outperforming the Dow Jones Industrial Average and the S&P 500. The stock trades at an extremely low price-to-earnings ratio of 6 and doesn't pay dividends.

If you liked this article you might like

Blame Amazon for Walmart's Surprising 2018 Outlook

Blame Amazon for Walmart's Surprising 2018 Outlook

Walmart's Quarter and Outlook Probably Have Wall Street Confused

Walmart's Quarter and Outlook Probably Have Wall Street Confused

Blackstone Group's Byron Wien: Investors Need Complacency Beaten Out of Them

Blackstone Group's Byron Wien: Investors Need Complacency Beaten Out of Them

Quick Tips: Now What Should Investors Do?

Quick Tips: Now What Should Investors Do?

Is the Market's Explosive Rally Off the Lows Fake?

Is the Market's Explosive Rally Off the Lows Fake?