The grades of four Software stocks are on the rise this week on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

Imperva Inc’s (NYSE:IMPV) grade is moving up to a B (“buy”) this week from last week’s C (“hold”). In Portfolio Grader’s specific subcategories of Earnings Revisions and Sales Growth, IMPV also gets A’s. The stock price has risen 9.6% over the past month, better than the 3.9% increase the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of IMPV stock.

Solera Holdings (NYSE:SLH) improves from a C to a B rating this week. Solera Holdings provides software and services to the automobile insurance claims processing industry. Investors seem to agree with the upgraded status of the stock, and have pushed the stock up 9% over the past month. For more information, get Portfolio Grader’s complete analysis of SLH stock.

Sapiens International (NASDAQ:SPNS) shows solid improvement this week. The company’s rating rises from a C to a B. Sapiens International is a global provider of information technology solutions. Wall Street seems to agree with the upgrade and has propelled the stock up 18.3% over the past month. For more information, get Portfolio Grader’s complete analysis of SPNS stock.

SeaChange International (NASDAQ:SEAC) gets a higher grade this week, advancing from a C last week to a B. SeaChange International is a developer, manufacturer, and marketer of digital video systems and services. Investors have pushed the stock price up 16.3% over the past month. For more information, get Portfolio Grader’s complete analysis of SEAC stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.