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

Shares of RentACenter, Inc. (RCII) have slumped 20.6% since January 1. Rent-A-Center operates in the rent-to-own industry in the United States. As of April 3, 2014, 18% of outstanding RentACenter, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of RCII stock.

The price of Cementos Pacasmayo SAA Sponsored ADR (CPAC) is down 20.7% since the first of the year. 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. Shares of the stock have been changing hands at an unusually rapid pace, up 4074.4% from the week prior. For more information, get Portfolio Grader’s complete analysis of CPAC stock.

Shares of Resolute Energy Corporation (REN) have fallen 21.1% since January 1. Resolute Energy explores for and produces oil and natural gas in the southern and western United States. For more information, get Portfolio Grader’s complete analysis of REN stock.

Since the first of the year, FTI Consulting, Inc. (FCN) has dipped 21.3%. FTI Consulting provides corporate finance and restructuring, economic, forensic and litigation, strategic communications and technology consulting services. As of April 3, 2014, 11% of outstanding FTI Consulting, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of FCN stock.

Shares of Clean Energy Fuels (CLNE) have slumped 32.3% since the first of the year. Clean Energy Fuels sells natural gas fueling solutions to its customers mainly in the United States and Canada. As of April 3, 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 Alpha Natural Resources, Inc. (ANR) have sunk 32.8% since the first of the year. Alpha Natural Resources produces, processes and sells steam and metallurgical coal. As of April 3, 2014, 22.2% of outstanding Alpha Natural Resources, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of ANR stock.

Shares of UTi Worldwide (UTIW) have slipped 34.3% since January 1. UTi Worldwide is a supply chain services and solutions company. For more information, get Portfolio Grader’s complete analysis of UTIW stock.

Since January 1, Weight Watchers International, Inc. (WTW) has plunged 35.5%. Weight Watchers is a provider of weight management services, operating globally through a network of company-owned and franchise operations. As of April 3, 2014, 19.9% of outstanding Weight Watchers International, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of WTW stock.

Since the first of the year, Aeropostale, Inc. (ARO) has dipped 41.2%. Aeropostale is a mall-based specialty retailer of casual apparel and accessories. As of April 3, 2014, 25.3% of outstanding Aeropostale, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of ARO stock.

Since the first of the year, Walter Energy (WLT) has tumbled 48%. Walter Energy is a producer and exporter of metallurgical coal for the global steel industry. As of April 3, 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.