The ratings of four Software stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Taomee Holdings’ (NYSE:TAOM) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Taomee Holdings produces children’s entertainment. In Portfolio Grader’s specific subcategories of Earnings Surprise and Margin Growth, TAOM also gets F’s. To get an in-depth look at TAOM, get Portfolio Grader’s complete analysis of TAOM stock.

This week, SRS Labs’ (NASDAQ:SRSL) rating worsens to a D from the company’s C rating a week ago. SRS Labs develops and licenses audio and voice enhancement technologies. The stock gets F’s in Earnings Growth and Margin Growth. For more information, get Portfolio Grader’s complete analysis of SRSL stock.

TeleNav Inc. (NASDAQ:TNAV) earns a D this week, moving down from last week’s grade of C. TeleNav provides location-based solutions. The stock gets F’s in Earnings Growth, Earnings Momentum, and Margin Growth. For a full analysis of TNAV stock, visit Portfolio Grader.

Red Hat’s (NYSE:RHT) rating weakens this week, dropping to a D versus last week’s C. Red Hat provides open source software solutions that customers are allowed to update, monitor and manage. The trailing PE Ratio for the stock is 62.70. To get an in-depth look at RHT, get Portfolio Grader’s complete analysis of RHT 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.