The idea of trend following is at the core of technical analysis. If a market or share is going up then the disciplined approach is to look for buying opportunities; and in a downtrend either sell, or sell short. So for many, quite rightly, everything begins with the trend.

But for this week we are taking a slight twist to the approach so far. I thought it would be interesting to look at what shares have actually underperformed the broader stock markets over the past year: is there something the market has missed and are these hidden gems about to play catch up?

I must admit to being initially sceptical about this approach. It is always dangerous to start thinking you know more than the market knows or the market has got something wrong. It is those sort of thoughts that can leave people to doggedly stick with their investment choices when all of the evidence suggests that maybe it was a wrong decision and it is time to sell, take a manageable loss and move on to something hopefully more profitable.

The initial shortlist comes via SharesScope’s data mining feature. Stock markets have been going up for more than five years. The criteria for the initial long list was shares that have gone down in the past six months and also over the past 12 months, clearly bucking the market. Out of the FTSE All-Share index there were 126 shares that met this criteria, a surprising 20% of the index constituents. Some of the companies are in what look like significant downtrends but many appear to be just going through a particularly long lasting correction and offer hopes for a bounce back. Let's look at three companies that appear on the search results.

Countrywide (CWD)

Buy 515p

Target 700p

Stop Loss 450p

Looking at the chart of FTSE 250 real estate agent Countrywide (CWD) feels like we are back in familiar territory. It is slightly down in price over the past 12 months so fits the criteria. There has been a much steeper slide since March where the share price is down almost 20%.

However, the share price movements during July and August offer some hope that this downtrend is over.

The rallies in price have managed to take out the late June highs at 531p, maybe the first sign that sentiment is once again shifting positive with buyers willing to chase the price higher.

It is early days for any new potential trend but since July there is a short term uptrend with higher highs and lows. Assuming there is going to be a recovery then an eventual run back to 700p does not seem over optimistic, with a stop loss below that July low of 460p.

GlaxoSmithKline (GSK)

Buy £14.60

Target £25.00

Stop Loss £13.50

The share price of drugs giant GlaxoSmithKline (GSK), has traded in a sideways range for much of the past 18 months, until recently. The plunge in July has made the chart a more interesting once again.

The share price fell in fairly short order from £15.60 to £13.60 and, while this fall was a sizeable one, it has not changed the longer term trend.

That trend goes back five years, probably not a coincidence as that is of course how long the bull market in stock markets has been running. That sharp move lower has spiked briefly through that trend but there is also strong support from November 2012 running ahead of £13.00. This may be a little wide for a stop loss in this instance, but remains a big level to watch.

So even though it has been a poor six to 12 months for GlaxoSmithKline, this sharp sell-off may be presenting an opportunity to buy in ahead of a snap-back towards the top of the trading range at £18.00. The current recovery has already been a strong one, so it seems reasonable that any weakness from here should tempt buyers in who missed it the first time around. Stop losses could go below the recent low of £13.60.

Centrica (CNA)

Buy 318p

Target 380p

StopLoss 295p

A blue chip giant that has not had the best of times recently is gas and utility business Centrica (CNA). The share price has been in decline for almost a year and is trading a good 20% off the 2013 highs.

Although it is early days in the potential turnaround, some signs are encouraging. The lows for this year ahead of 300p have held again during July and August. This does suggest that market sees value down at current levels.

Our old friend - the trend - is still intact. This one goes back to 2003 with support coming in around the 290p mark. So for longer term holders, it would take weakness through this level to suggest that something was going seriously awry with the bigger picture. We will use a slightly tighter stop loss for this idea, the other side of the recent lows.

While it seems unlikely that if Centrica is going to recover, it is going to hand brake turn and race away from current levels, the 320p mark does look like a low risk/potential high return entry point to take a position and wait to see if sentiment continues to shift.