The ratings of 13 Software stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This week, NetSuite Inc.’s (N) rating worsens to a D from the company’s C rating a week ago. NetSuite Inc. provides relationship management software solutions. The company also gets F’s in return on equity. For more information, get Portfolio Grader’s complete analysis of N stock.

Aspen Technology, Inc. (AZPN) declines this week from a C to a D. Aspen Technology, Inc. is a global provider of mission-critical process optimization software solutions, which are designed to manage and optimize plant and process design, operational performance, and supply chain planning. For more information, get Portfolio Grader’s complete analysis of AZPN stock.

PTC Inc. (PTC) slips from a C to a D this week. The company also gets F’s in sales growth, operating margin growth, earnings growth, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of PTC stock.

This week, ACI Worldwide, Inc. (ACIW) drops from a C to a D rating. ACI Worldwide, Inc. develops, markets, installs, and provides support for a line of products and services that facilitate electronic payments. The company also gets F’s in earnings revisions. For more information, get Portfolio Grader’s complete analysis of ACIW stock.

QAD Inc. Class A’s (QADA) rating weakens this week, dropping to a F versus last week’s D. QAD Inc. Class A provides supply-chain-enabled enterprise resource planning software for mid-range and large multinational manufacturing companies. The company also gets F’s in sales growth, earnings revisions, earnings surprise, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of QADA stock.

This is a rough week for Infoblox Inc. (BLOX). The company’s rating falls to D from the previous week’s C. Infoblox Inc. develops, markets, and sells automated network control solutions worldwide. For more information, get Portfolio Grader’s complete analysis of BLOX stock.

Changyou.com Ltd. Sponsored ADR Class A (CYOU) gets weaker ratings this week as last week’s D drops to a F. Changyou.com Ltd. Sponsored ADR Class A develops and operates online games in China. The company also gets F’s in sales growth and earnings momentum. For more information, get Portfolio Grader’s complete analysis of CYOU stock.

Cheetah Mobile, Inc. ADR Class A (CMCM) is having a tough week. The company’s rating falls from a D to a F. The company also gets F’s in earnings growth, earnings revisions, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of CMCM stock.

Attunity Ltd (ATTU) earns a D this week, moving down from last week’s grade of C. Attunity Ltd provides information availability software solutions for real-time data integration, application release automation, and managed file transfer. The company also gets F’s in earnings revisions, earnings surprise, and return on equity. For more information, get Portfolio Grader’s complete analysis of ATTU stock.

KongZhong Corp. Sponsored ADR (KZ) experiences a ratings drop this week, going from last week’s C to a D. The company also gets F’s in sales growth and operating margin growth. For more information, get Portfolio Grader’s complete analysis of KZ stock.

Slipping from a D to a F rating, Asure Software, Inc. (ASUR) takes a hit this week. Asure Software, Inc. provides on-demand workforce management software and services worldwide. The company also gets F’s in earnings growth, earnings revisions, earnings surprise, and return on equity. For more information, get Portfolio Grader’s complete analysis of ASUR stock.

MIND C.T.I. Ltd. (MNDO) declines this week from a C to a D. MIND C.T.I. Ltd. is a developer, manufacturer, and marketer of real-time and off-line billing and customer care software for communication providers. The company also gets F’s in sales growth. For more information, get Portfolio Grader’s complete analysis of MNDO stock.

Slipping from a C to a D rating, Covisint Corp. (COVS) takes a hit this week. The company also gets F’s in sales growth, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of COVS 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.