LONDON -- In the last three months, the FTSE 100 is up 3.1%. That's a decent performance. The shares below, however, are up an average of 27.9% each.

What has led to such huge gains? Could further rises be possible?

There are numerous reasons why a company's shares can rise sharply. These include takeover talks, improved trading, or simply an increased appetite for investment risk. It is vital to try to understand what has led to a share's rise before we can determine if further advances could be in the cards.

These are the 12 largest companies that have outperformed by more than 15% in the last three months.

Company

Price (pence)

3-Month Price Change

P/E (forward)

Yield (forward)

Market cap (millions of pounds)

Barclays (LSE: BARC.L)

226

32.3%

6.9

2.9%

27,591

Lloyds

38

23.4%

18.3

N/A*

26,683

Royal Bank of Scotland

261

25.4%

13.2

0%

15,690

Fresnillo

1959

28.7%

30.3

1.7%

14,048

Randgold Resources

7775

28.6%

23.2

0.5%

7,144

Standard Life

279

19.8%

13.8

5.2%

6,584

Polymetal International

1146

27%

12.9

1.7%

4,385

Aberdeen Asset Management

320

21.7%

14.9

3.3%

3,680

ITV (LSE: ITV.L)

92

20.9%

11.0

2.5%

3,597

Aegis

236

42.7%

19.1

1.5%

2,765

TUI Travel (LSE: TT.L)

246

40.3%

10.4

4.8%

2,747

Sports Direct International (LSE: SPD.L)

387

24.5%

16.7

2.8%

2,317

Source: Stockopedia. *Large estimate variation.

Four stood out in particular

1. Barclays
Barclays shares have come storming back since the removal of its chief executive. Like its peers Royal Bank of Scotland and Lloyds, Barclays has also benefited from improved sentiment in the eurozone. In recent weeks, a lot of heat has been taken out of the LIBOR furor, and Barclays has a new boss.

Despite this rise, Barclays still trades at an attractive valuation. The consensus earnings per share forecast for 2012 is 32.9 pence. The expected dividend is 6.45 pence per share. This means that the shares currently trade on a forward price-to-earnings ratio of 6.9, with a dividend yield of 2.9%.

Barclays is expected to deliver 10.5% earnings growth in 2013, with the dividend advancing 11.7%. It is rare to find a company with that level of forecast growth trading on such a low rating. Clearly, the market believes there is a considerable risk to Barclays' future earnings. Investors must decide whether these fears are merited.

2. ITV
ITV has been keen to point out the company's balance sheet recovery. With its July interims, ITV reported that it had a net cash position of 92 million pounds. This is a dramatic turnaround from the end of 2009: At that point, ITV was 612 million pounds in debt.

Just as the debt position was different in 2009, so were ITV's earnings: That year, the company reported EPS of 2.9 pence. The market expects earnings of 8.4 pence per share for 2012. The shares have also been helped recently by takeover speculation.

ITV demonstrates two things. First, it shows how dramatically the financial position of a cyclical company can change when business picks up. Second, ITV supports my theory that there is always a company somewhere that is someone else's takeover target -- whatever the market conditions.

The challenge now for ITV management is to diversify its revenue beyond TV advertising. This seems to be working. With its most recent results, the company posted a 26% growth in nonadvertising revenue.

3. TUI Travel
TUI Travel is the company behind Thomson, airtours, and laterooms.com. Its rise in the last quarter is a great demonstration of what can happen when the market realizes it was wrong to write a company off.

The difficulties experienced by rival Thomas Cook have affected sentiment toward TUI. Between March and August, TUI investors suffered. The company's share price never got past 200 pence, falling as low as 158 pence. At its low, TUI Travel shares traded at just 6.7 times the consensus EPS estimate for 2012.

Normally, the market reserves that kind of miserable rating for companies it believes are going backwards. In TUI's case, I would suggest that the fall was down to the market believing that the company's future earnings were highly uncertain. TUI shares took off as the eurozone fears lifted. The shares were also helped by an encouraging statement on sales for the key summer period.

TUI travel has increased its shareholder dividend in every year since 1999.

4. Sports Direct International
Sports Direct looks set to capitalize on the demise of JJB Sports. Last week, Sports Direct announced that it would be taking on 20 JJB stores and a property in Wigan. It appears that Sports Direct has cherry-picked the best stores in the JJB portfolio. It has also taken the JJB website.

Analysts hope Sports Direct will thrive in a less competitive sports retailing environment. After a strong run that began in August, the shares now trade at 16.7 times the consensus 2013 earnings estimate. To meet these expectations, Sports Direct has to deliver a 41.5% increase in EPS.

That's no mean feat. In a trading statement last month, the company reported that a 25.3% rise in sales had led to a 20.4% increase in gross profit. No doubt that the acquisitions from JJB will help Sports Direct toward the market's expectations.

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