This week, these ten stocks have the worst year-to-date performance. Each of these also rates an “F” (“strong sell”) on Portfolio Grader.

Since January 1, Cementos Pacasmayo SAA Sponsored ADR (CPAC) has plunged 18.9%. Cementos Pacasmayo engages in producing, manufacturing, distributing and selling cement blocks, cement bricks, concrete pre-mixed bricks and other construction materials, and its by-products in the northern part of Peru. For more information, get Portfolio Grader’s complete analysis of CPAC stock.

Share prices of Cencosud S.A. Sponsored ADR (CNCO) are down 19.3% since the first of the year. Cencosud operates as a multi-brand retailer in Argentina, Brazil, Chile, Peru and Colombia. The stock has a trailing PE Ratio of 56.90. For more information, get Portfolio Grader’s complete analysis of CNCO stock.

Shares of FTI Consulting, Inc. (FCN) have dipped 20.6% since the first of the year. FTI Consulting provides corporate finance and restructuring, economic, forensic and litigation, strategic communications, and technology consulting services. As of March 27, 2014, 11.6% of outstanding FTI Consulting, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of FCN stock.

Since the first of the year, RentACenter, Inc. (RCII) has tumbled 22.4%. Rent-A-Center operates in the rent-to-own industry in the United States. As of March 27, 2014, 18% of outstanding RentACenter, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of RCII stock.

Shares of Clean Energy Fuels (CLNE) have fallen 30.8% since January 1. Clean Energy Fuels sells natural gas fueling solutions to its customers mainly in the United States and Canada. As of March 27, 2014, 18.9% of outstanding Clean Energy Fuels shares were held short. For more information, get Portfolio Grader’s complete analysis of CLNE stock.

Shares of UTi Worldwide (UTIW) have sunk 30.8% since the first of the year. UTi Worldwide is a supply chain services and solutions company. Shares of the stock have been changing hands at an unusually rapid pace, up 163.5% from the week prior. For more information, get Portfolio Grader’s complete analysis of UTIW stock.

Since the first of the year, Alpha Natural Resources, Inc. (ANR) has dipped 31.2%. Alpha Natural Resources produces, processes and sells steam and metallurgical coal. As of March 27, 2014, 24.1% of outstanding Alpha Natural Resources, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of ANR stock.

Shares of Aeropostale, Inc. (ARO) have slumped 34.1% since January 1. Aeropostale is a mall-based specialty retailer of casual apparel and accessories. As of March 27, 2014, 26.5% of outstanding Aeropostale, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of ARO stock.

Since January 1, Weight Watchers International, Inc. (WTW) has fallen 37.4%. Weight Watchers is a provider of weight management services, operating globally through a network of company-owned and franchise operations. As of March 27, 2014, 20.5% of outstanding Weight Watchers International, Inc. shares were held short. Shares of the stock are being traded at a very rapid pace, up 104.5% from the week prior. For more information, get Portfolio Grader’s complete analysis of WTW stock.

Since the first of the year, the price of Walter Energy (WLT) is down 48.6%. Walter Energy is a producer and exporter of metallurgical coal for the global steel industry. As of March 27, 2014, 13.3% of outstanding Walter Energy shares were held short. For more information, get Portfolio Grader’s complete analysis of WLT 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.