Dave Sullivan had a bad day on Wednesday. It was the end of the tax year and he wanted to take advantage of the £7,100 capital gains tax allowance for the financial year by selling some of his shares.
But Mr Sullivan - and many like him - were not to be rewarded. The stock exchange broke down for eight hours, making it impossible for investors to buy and sell shares. It reopened at 3.30pm and stayed open until 8pm. But Mr Sullivan was not able to make his trade.
"It was a shambles. I left the trade until Wednesday to maximise my tax advantages. I think I lost about £1,000 of tax advantages," he said.
Mr Sullivan, who sells computers and lives in Rayleigh, Essex, is one of a growing number of small investors who takes an active interest in the stock market that the chancellor Gordon Brown approves of.
But he did not feel very encouraged on Wednesday. He felt that the unavoidable problems caused by the computer glitch at the stock exchange were compounded by official responses. He said: "It was a shambles and very poorly handled. I am a small investor and the fact that I was not able to trade was not my fault. I think there should be some compensation, or the tax year could have been extended."
He should not hold his breath. Gordon Brown held an emergency meeting and decided not to shift the dates of the financial year. The stock exchange - which said that two thirds of a normal day's business eventually went through - is not set to give compensation.
But the two-thirds estimate is based on a normal day when the stock exchange usually oversees about 120,000 trades. The last day of the tax year was expected to be frantic and the computer breakdown threw brokers into chaos.
Chris Ring, managing director of Natwest Stockbrokers, said: "Most of our customers who wanted to trade for tax reasons were able to do it. But that was because of the goodwill of the brokers and market makers who stayed late."
But he added: "We found it difficult to shift large numbers of shares as the screens with prices on were closed at 6.30pm so prices were negotiated on the basis of closing price and demand."
Some brokers found that market makers - the people who buy and sell to brokers - were unwilling to quote prices as they were unsure of the movement of the market.
Mike Hines, joint managing director of the market makers Winterflood Securities, said: "We consulted the FSA and we were not afraid to stand up and be counted. Our spreads were tentative because of the way the market was anyway, after so much volatility in America."
People may have lost out on their capital gains allowance, but the problems will not affect other investments. Jason Hollands, deputy managing director of the stockbrokers Best Investment, explained: "ISAS are not affected. As long as people got their applications in for ISAs to the fund manager by the end of the tax year they are covered."
Mr Sullivan's loss is not on the same scale as some, according to John Whiting, tax partner at the accountant PriceWaterhouseCoopers. "There are some people who made serious profit on their shares, say £100,000, in the tax year just ended and wanted to sell enough to bring the amount of tax they are liable for right down. So the fact they could not sell the roughly £90,000 of shares they needed to shift to approach the capital gains allowance means that they will be heavily penalised."
Mr Whiting has some advice for next year: "Don't wait until the very last moment. A number of problems could arise - you may not be able to find a broker, he may have a heart attack or, of course, the stock market could go down."