Abstract: | Investment is booming: not only in the UK but also in the US, Japan and in Europe. In this Briefing Paper we seek to understand why this is happening – a global phenomenon clearly requires a global not a local explanation – and to consider whether the boom will continue. To this end (and not in order to discriminate between alternative theories of investment), we examine the main theories of investment and show that recent developments are consistent with models based on the accelerator, or which emphasize the cost of finance or which depend upon stock market valuation effects. And, no matter which theory holds, the implication is the same: investment will weaken in 1989 and this is an important element in our forecast of slower world and UK growth next year. But there is an alternative view, which implies a more optimistic outlook. The theories which we consider are essentially cyclical: they focus on the key role of (volatile) investment spending in the business cycle. It may well be that the present surge in investment is a long-tern, structural phenomenon reflecting either a shift in the pattern of world demand or the spread of computer-based technology, which has raised the efficiency of investment. In this case, and notwithstanding this year's surge in investment, tighter monetary policy and the stock market crash, the present boom in investment may have a lot further to run. |