Each business day, TheStreet.com Ratings TheStreet.com Ratings compiles a list of the top five stocks in one of five categories -- fast-growth, all-around value, large-cap, mid-cap and small-cap -- based on data from the close of the previous trading session. Today we focus on mid-caps.

These are stocks of companies that have market capitalizations of between $500 million and $10 billion that rank near the top of all stocks rated by our proprietary quantitative model, which looks at more than 60 factors.

The stocks must also be followed by at least one financial analyst who posts estimates on the Institutional Brokers' Estimate System. They are ordered by their potential to appreciate.

Note that no provision is made for off-balance-sheet assets such as unrealized appreciation/depreciation of investments, market value of real estate or contingent liabilities that might affect book value. This could be material for some companies with large underfunded pension plans.

First Financial ( THFF) is a bank holding company whose subsidiaries provide various financial services in Indiana and Illinois. It has been rated a buy since August 2006 because of its solid stock price performance and net income growth.

For the fourth quarter of fiscal 2008, First Financial reported weak revenue results, but declining revenue does not appear to have hurt the company's bottom line. Earnings per share improved from 49 cents in the fourth quarter of fiscal 2007 to 55 cents in the most recent quarter. Net income also increased, rising 12.4% from $6.4 million to $7.2 million. In addition, cash and cash equivalents increased from $74.3 million to $76.8 million.

Investors have apparently begun to recognize these and other positive factors, driving First Financial's stock price up 34.4% over the past year. Although this puts the stock at a premium valuation compared to its peers, we feel that the company's strengths justify the higher price level at this time.

Pegasystems' ( PEGA) business management software helps companies manage complex, changing business processes by automating decision-making and the implementation of those decisions. We have rated the company a buy since May 2008. This rating is based on the company's growth, solvency, and expanding profit margins.

For the fourth quarter of fiscal 2008, the company reported revenue growth of 26.9% year-over-year. Continuing an impressive record of EPS growth, Pegasystems' EPS improved significantly, rising from 3 cents to 8 cents. Net income also increased in the fourth quarter, surging 99.6% from $1.4 million to $2.8 million. Both revenue and net income growth exceeded the averages for the Software industry. Pegasystems' gross profit margin is rather high at 64.8%; it has increased from the same quarter a year ago. The company has no debt to speak of, and its resulting debt-to-equity of zero can be seen as a favorable sign. In addition, Pegasystems maintains a quick ratio of 3.4, which clearly demonstrates its ability to cover short-term cash needs.

Management reported that the company's fourth quarter revenue was a record for the company. Pegasystems also achieved record new license signings for the quarter. Looking ahead to fiscal 2009, the company currently expects full-year revenue to top $250 million, while net income could surpass $17 million on a GAAP basis. The company's weak operating cash flow is a concern, but we feel that the strengths detailed above outweigh any weaknesses at this time.

Silgan Holdings ( SLGN) manufactures metal and plastic consumer goods packaging products, including metal food containers, vacuum closures for food and beverage products, and high density polyethylene and polyethylene terephthalate containers for the personal care market. Our buy rating for this stock has been in place since May 2004. The rating is based on such strengths as the company's growth, efficiency, and total return.

For the fourth quarter of fiscal 2008, Silgan reported slight revenue growth of 8.4% year over year. This growth appears to have helped boost EPS, which improved 23.1% when compared to the same quarter a year ago, continuing a trend of positive EPS growth. We feel that this trend should continue. Net income also increased in the fourth quarter, rising 22.3% from $19.9 million to $24.4 million. A slight increase in return on equity can be seen as a modest strength for the organization, and the stock's price has risen over the past year, reflecting earnings growth and other positive factors.

Management announced that both fourth quarter and full year earnings were records for the company. Looking ahead to fiscal 2009, the company anticipates adjusted net income per diluted share in the range of $3.75 to $3.95 for the full year. Although the company has shown generally poor debt management, we feel that the strengths indicated here outweigh any weaknesses and justify the stock's high price.

Tyler Technologies ( TYL) provides integrated information management solutions and services for local governments in the U.S., Canada, Puerto Rico and the UK. It has been rated a buy since July 2005 because of its efficiency, solvency, revenue growth, and solid stock price performance.

For the fourth quarter of fiscal 2008, Tyler reported revenue growth of 15.1% year over year. This was higher than the industry average of 7.5%, but does not appear to have helped boost the company's bottom line, as EPS decreased 6.7% when compared to the same quarter a year ago. The company has shown a pattern of declining EPS over the past year, but our model anticipates a reversal in this trend in the year ahead. The company has a strong gross profit margin of 45.9%, which has increased from the same quarter last year. Tyler's return on equity can also be considered a modest strength, as it has improved slightly. In addition, a very low debt-to-equity ratio of 0.1 implies that the company has managed its debt levels very successfully.

Management was pleased with both the fourth quarter and full year results in fiscal 2008, stating that both were strong and that the company had a positive outlook for fiscal 2009. The company announced 2009 guidance, anticipating full-year total revenue between $292 million and $298 million. Despite the company's weak operating cash flow, we feel that its strengths outweigh any potential weakness that could affect future financial results.

Sybase ( SY) provides enterprise and mobile software solutions for information management, development and data integration in commerce, communications, finance, government, defense, manufacturing, transportation and healthcare. We have rated the company a buy since October 2004. This rating is supported by such factors as the company's growth, efficiency and solvency.

Sybase reported results for the first quarter of fiscal 2009 on April 22, and we will be updating our model and our rating accordingly. However, the current rating is based on the fourth quarter of fiscal 2008. Sybase reported slight revenue growth of 3.3% year over year in the fourth quarter. This growth does not appear to have trickled down to the company's bottom line, however, as EPS dropped from 81 cents to 58 cents. Net operating cash flow improved slightly when compared to the same quarter last year, increasing 1.3% to $84.5 million. The gross profit margin is very high at 80.30% and has increased from the prior year's quarter. Sybase's debt-to-equity ratio is low at 0.6, but is higher than the industry average, indicating that the company may need to further evaluate its debt management. The return on equity can be construed as a modest strength of the organization, as it has improved slightly when compared to the same quarter of last year.

Management announced that its quarterly and full-year results were the best in company history. Looking forward to the first quarter of fiscal 2009, Sybase expects to achieve revenue in the range of $260 million to $270 million, along with non-GAAP fully diluted EPS in the range of 40 cents to 42 cents and GAAP EPS in the range of 27 cents to 29 cents. Sybase has shown sub par net income growth recently, but we feel that the strengths detailed above outweigh that weakness at this time.

Our quantitative rating, which can be viewed for any stock through our stock screener stock rating screener, is based on a variety of historical fundamental and pricing data and represents our opinion of a stock's risk-adjusted performance relative to other stocks.

However, the rating does not incorporate all of the factors that can alter a stock's performance. For example, it doesn't always factor in recent corporate or industry events that could affect the stock price, nor does it include recent technology developments and competitive dynamics that may affect the company.

For those reasons, we believe a rating alone cannot tell the whole story and should be part of an investor's overall research.