The overall ratings of four internet and web service stocks are down on Portfolio Grader this week. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Marin Software, Inc. (MRIN) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). In Portfolio Grader’s specific subcategories of Equity and Cash Flow, MRIN also gets F’s. To get an in-depth look at MRIN, get Portfolio Grader’s complete analysis of MRIN stock.

Reis, Inc. (REIS) is on the decline this week, earning a D (“sell”) after receiving a C (“hold”) last week. Reis is engaged in the business of providing commercial real estate market information and analytical tools for its customers. The stock gets F’s in Earnings Momentum and Earnings Surprise. For more information, get Portfolio Grader’s complete analysis of REIS stock.

Slipping from a D to an F rating, iPass (IPAS) takes a hit this week. iPass offers enterprise mobility services on a global basis by providing services that simply, smartly and openly facilitate network access from mobile devices while providing the enterprise with visibility and control over their mobile ecosystem. The stock gets F’s in Earnings Revisions, Equity, Cash Flow and Sales Growth. To get an in-depth look at IPAS, get Portfolio Grader’s complete analysis of IPAS stock.

Velti (VELT) is having a tough week. The company’s rating falls from a D to an F. Velti is a global provider of mobile marketing and advertising solutions. The stock gets F’s in Earnings Growth and Earnings Momentum. For more information, get Portfolio Grader’s complete analysis of VELT 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.