From July 2010 the Capital Gains Tax rate rose from a sensible 18% under the Labour government to an uncompetitive 28%. Presumably the idea was to collect more revenue from it. Even the Treasury, however, expected a dip in the first full year after its implementation (2012-13, as CGT is paid the year after the gains on which it is calculated). They then expected revenues to pick up.
In the 2013 Budget the Treasury gave new forecasts, where they accepted that CGT revenues would be lower in 2012-13 at £3.9bn but would bounce up to £5.1bn the following year. By the time of Budget 2014 they had to revise the figures again. This time they forecast revenues lower in both 2012-13 and 2013-14 at £3.9bn in each year, £400 m down on the £4.3bn collected in 2011-12. A massive £1.2 bn of forecast revenue had gone missing, despite the economy growing faster than they expected. Clearly the taxpayer has lost out so far from the increase in the rate of CGT. If it had stayed at 18% 2011-12 might have come in a bit lower, as there would have been no need for some to pre-empt the higher rate in the week or two of rumours that preceded the imposition in June 2010. The following two years would doubtless have seen considerably more revenue than the Treasury will receive at the higher rate.
CGT is the most easily avoidable tax. Many individuals and companies simply refuse to sell assets which are sitting on large gains, even though they would rather switch them into something more useful for their current needs. Rich individuals who have power to switch the domicile of themselves or their assets find it more worthwhile to do so if they are thinking of selling something at a good profit. Individuals with losses as well as gains make sure they take offsetting losses when rejigging their investments. High rates of CGT are probably stopping people selling second homes in London, even though they may not need them any more, helping to fuel the boom.
I remember making the case against a higher rate of CGT at the time of the 2010 budget. The Lib Dems wanted a 40% rate, I wanted to keep Labour’s rate, and we ended up with a compromise. It’s more proof that the Treasury do not have a good model of tax receipts. Just as they under estimate rising revenues when rates are cut, so in this case they have grossly overestimated the gains so far from a higher CGT rate.