Though more than pounds 8bn of the total windfall payouts will be injected into the domestic economy, Fleming's research shows that the high import content of this expenditure will dilute the effect on Britain's GDP to 0.5 per cent this year.
Robert Fleming's economic adviser, Peter Warburton, says that with the surge in consumer confidence over the past six months expected to be reversed in the autumn there is no need to push interest rates higher to fend off a feared high street boom: "We found only a small minority of the respondents whose new-found spending confidence will continue at the expense of saving. The surge in consumer confidence is likely to be reversed quite rapidly this autumn."
The findings of the report echo comments from the Bank of England in which it suggested the four quarter-point interest rate rises in as many months would be enough to keep inflation on track to meet its 2.5 per cent target.
The Bank last week announced plans for its own investigation into the economic effects of the windfall factor.
Mr Warburton said: "The comparison with 1988, when real wages rose strongly and home-owners borrowed to excess, is poorly made. On the basis of the survey evidence, there is no case for hitting the consumer with further interest rate increases."
The survey is one of the first to attempt to pinpoint what former building society members have done with the windfalls that gave investors and borrowers an average of more than pounds 2,000 each in shares. Fleming calculated that the flotations of Halifax, Alliance & Leicester, Woolwich and Norwich Union, and those such as Northern Rock that were still to come, would release a total of pounds 8.2bn of spending power. Of that, pounds 2.1bn would be spent on home improvements, furnishings and DIY, pounds 2.1bn on holidays and travel and pounds 700m on electrical items for the home.
The detailed breakdown of the survey by age and social class revealed interesting differences in spending patterns. A fifth of young ABC1 professionals between the ages of 15 and 34 spent most of their windfalls on a car or motorbike, a much greater proportion than older people in the same social class.
A quarter of young C2DEs chose to spend their cash on electrical items. There was hardly any preference among ABC1s for electrical goods.
Middle-aged and older people from professional and managerial classes were more likely to use their windfalls to travel.
More than three quarters of windfall shares have been saved or used to repay debt. The high savings rate is expected to inject pounds 4bn of new business into the PEP and unit trust industry, but most of the new PEP accounts will be with the converting institutions themselves. Banks and building societies are expected to receive up to a further pounds 4bn of cash inflows.
A separate Harris poll of 168 MPs showed three quarters were in favour of maintaining the mutual status of building societies and life companies. The report was commissioned by NPI, the pensions and investment management group.