S&P 500 companies with the greatest increase in short-selling

S&P 500 companies with the greatest increase in short-selling ; Short-selling is an investment technique that allows an investor to make money when the value of a stock falls. Short-sellers, however, lose money when the share price rises. And because share prices could rise to infinity, a reckless short position could lead to incredibly large losses. Because short-selling requires borrowing, an individual or institution must meet several requirements (including background checks) to engage in short-selling. Thus, short-sellers are seen as more sophisticated than the average investor.

The Standard & Poor's 500 Index (S&P 500) refers to 500 companies that have common stock traded in the U.S. stock market. They are all large-cap companies that serve as representatives of their industries in the U.S. economy. It is one of the most commonly used benchmarks for the health of the stock market. Standard & Poor's committee of analysts and economists has carefully chosen each stock on this list.

In general: When there is an INCREASE in short-selling, short-sellers seem to think the names will DROP in value. When there is an DECREASE in short-selling, short-sellers seem to think the names will RISE in value.

Without further ado, a list of S&P 500 companies with the greatest increase in short-selling. Short-sellers think these stocks are in trouble, do you agree?

List sorted by percent of change in short-seller activity. (Click here to access free, interactive tools to analyze these ideas.)

1. Cerner Corporation (Nasdaq: CERN ) :
Health Care Information Services Industry. Market cap of $10.94B. Current price at $64.16. Shares shorted in the recent month at 16.35M, an increase from the previous month's 8.25M shares. This represents 5.69% of the company's share float. The stock is a short squeeze candidate, with a short float at 11.52% (equivalent to 14.01 days of average volume). The stock has had a couple of great days, gaining 5.09% over the last week.

2. J. C. Penney (NYSE: JCP ) :
Department Stores Industry. Market cap of $6.70B. Current price at $31.24. Shares shorted in the recent month at 28.26M, an increase from the previous month's 23.01M shares. This represents a 3.64% of the company's share float. The stock is currently stuck in a downtrend, trading -5.19% below its SMA20, -7.79% below its SMA50, and -7.54% below its SMA200. The stock has gained 28.45% over the last year.

3. Advanced Micro Devices (NYSE: AMD ) :
Semiconductor Industry. Market cap of $5.33B. Current price at $7.61. Shares shorted in the recent month at 83.57M, an increase from the previous month's 68.98M shares. This represents a 2.52% of the company's share float. This is a risky stock that is significantly more volatile than the overall market (beta = 2.19). The stock has had a couple of great days, gaining 20.53% over the last week.

4. Best Buy (NYSE: BBY ) :
Electronics Stores Industry. Market cap of $11.05B. Current price at $29.33. Shares shorted in the recent month at 41.95M, an increase from the previous month's 35.39M shares. This represents a 2.18% of the company's share float. The stock is a short squeeze candidate, with a short float at 14.01% (equivalent to 5.98 days of average volume). The stock has lost 15.93% over the last year.

5. Teradata (NYSE: TDC ) :
Diversified Computer Systems Industry. Market cap of $9.67B. Current price at $56.99. Shares shorted in the recent month at 5.75M, an increase from the previous month's 3.00M shares. This represents a 1.64% of the company's share float. The stock has gained 73.76% over the last year

6. MEMC Electronic Materials (NYSE: WFR ) :
Semiconductor Industry. Market cap of $1.86B. Current price at $8.22. Shares shorted in the recent month at 15.17M, an increase from the previous month's 11.44M shares. This represents a 1.62% of the company's share float. The stock has had a couple of great days, gaining 5.91% over the last week.

7. Nicor (NYSE: GAS ) :
Gas Utilities Industry. Market cap of $2.55B. Current price at $55.85. Shares shorted in the recent month at 2.36M, an increase from the previous month's 1.69M shares. This represents a 1.49% of the company's share float. The stock is a short squeeze candidate, with a short float at 5.24% (equivalent to 8.23 days of average volume). The stock has gained 32.76% over the last year.

8. Quest Diagnostics (NYSE: DGX ) :
Medical Laboratories & Research Industry. Market cap of $8.97B. Current price at $56.24. Shares shorted in the recent month at 6.59M, an increase from the previous month's 4.38M shares. This represents a 1.42% of the company's share float. The stock has gained 28.38% over the last year.

9. AutoNation (NYSE: AN ) :
Auto Dealerships Industry. Market cap of $5.78B. Current price at $39.39. Shares shorted in the recent month at 12.76M, an increase from the previous month's 12.12M shares. This represents a 1.26% of the company's share float. The stock is a short squeeze candidate, with a short float at 10.08% (equivalent to 14.1 days of average volume). The stock has had a good month, gaining 11.43%.

10. Tyson Foods (NYSE: TSN ) :
Meat Products Industry. Market cap of $6.93B. Current price at $18.01. Shares shorted in the recent month at 21.98M, an increase from the previous month's 18.44M shares. This represents a 1.17% of the company's share float. The stock has gained 2.47% over the last year.

Analyst ratings sourced from Zacks Investment Research.