Tullow came up trumps last week and proved to be the common factor in the top performing portfolios. Both the weekly winner and the portfolio heading the overall leaderboard contained the exploration stock which rose by a hefty 20 per cent in week four alone.

The rise helped bolster Fry, the portfolio managed by Garda Sergeant Tom Egan, which gained 18.5 per cent on the week to earn him a cash prize of £1,000. Sgt Egan, who heads up the social sciences section in the Garda College in Templemore, says he opted for high-tech and exploration stocks generally rather than the more traditional banking or food shares. He plumped for Tullow in particular because oil stocks generally were rising but he felt Tullow had had a slow few weeks and was due a bit of a bounce.

However, he says that although he has got the hang of when to buy, he has yet to master the tricky art of deciding when best to sell. Sgt Egan says he developed an interest in the stock market after qualifying for free Irish Permanent shares as part of the flotation five years ago. He has since acquired shares in Norwich Union and First Active and also stands to get Canada Life shares so he fully intends to take advantage of his year's free share dealing through AIB.

Topping the overall leaderboard four weeks into the competition is the man who says he invented the Business Expansion Scheme (BES) concept. Mr William Kingston of the Business School in Trinity College picked shares which have increased in value by nearly 50 per cent since Sharetrack 100 began, putting him ahead of the posse which includes his son Christopher and last week's leader, Dr Edward Staunton.

Although Dr Staunton has relinquished the Number One spot, he retains no less than 12 portfolios in the Top 50 and remains a serious contender.

So what strategies are proving popular at present? The number of shares in each portfolio is decreasing with around half of the portfolios now containing less than the minimum of six shares they started out with.

Those who are languishing far behind could consider going for broke by narrowing their portfolio to include just a handful of shares - or even a single stock - which they think will significantly outperform in a bid to make up some ground or even win the weekly prize.

Those who think they have little or no chance of either should not despair. Polo shirts will be given out to deserving causes over the coming weeks. Write to us at Sharetrack 100, The Irish Times, 11/15 D'Olier Street, Dublin 2 with your tale of woe. Those who sold Tullow just ahead of Week Four will merit special consideration.