The Short View: Baby boom and gloom
The idea that demographic changes may drive financial markets is one that regularly inspires commentators. Back in the 1990s, many people were convinced that it was the baby boomers who were behind the bull market.
But if demographics are the key factor, the outlook is not very encouraging, according to Tim Bond of Barclays Capital. Slow economic growth, weak stock markets and rising bond yields may be in store.
The link between demographics and savings is based on the life cycle theory of investment; young people borrow, the middle aged save and the elderly run down their savings. Savings should be highest when the middle aged (35-54 year olds) are a large proportion of the population.
Furthermore, if the supply of savings is high, the price of savings, the level of yields, will be low. Conversely, when the population is heavily weighted towards dependents, the supply of savings will be low and the level of yields high.
As Mr Bond points out, this did happen in the 1970s when the baby boomers were still young. There is a strong link between the US long bond yield and the ratio of debtors (25-34) plus retired (over 65) to the middle aged. The same link shows up in the UK. Since the ratio of dependents is set to rise as the baby boomers retire, that suggests bond yields are headed higher.
Bad news for those who are invested in bonds. But what about equities? There also appears to be a link between the level of share prices and the demographic breakdown, Bond notes. “When the growth rate for the retired is slowing or negative, the real price of equities tends to be high” he says. The popping of the dotcom bubble in 2000 coincided with a peak in the high savings age cohort (the middle aged) as a proportion of the population. Alas as the baby boomers retire, and cash in their savings, real share prices should decline.
Nor is that the end of the gloom. Despite the presence of the baby boomers, the savings ratio has been low. This is because asset prices have been so strong; a small amount of savings have gone a long way. If markets falter, the middle aged will have to increase their proportion of income they save, slowing demand and economic growth.
生育高峰与经济关系密切
人口变化可能推动金融市场，这是市场评论员时常撰写的题目。在20世纪90年代，很多人曾经深信，令市场走牛的动力来自婴儿潮期间出生的人。
但根据巴克莱资本(Barclays Capital)的蒂姆?邦德(Tim Bond)的说法，如果人口是关键因素，那么市场前景就不太令人鼓舞。将来慢慢可能出现的情况是：经济增长低迷，股票市场疲软，债券收益率持续升高。
人口和储蓄之间的联系基于投资的生命周期理论：年轻人借钱消费，中年人储蓄，老年人则花光积蓄。当中年人(35至45岁)在人口中的比例占大头时，储蓄率应是最高的。
此外，如果用于储蓄的资金量很大，储蓄的价格，即储蓄收益率将走低。相反，当人口中受赡养人群比例非常大时，用于储蓄的资金就会较少，储蓄收益率就会较高。
如同邦德先生所指出的，这一现象在20世纪70年代的确出现过，当时婴儿潮期间出生的人尚年轻。美国的长期债券收益率与借债者(25至34岁)，退休者(65岁以上)与中年人人口之间的比例有着非常大的联系。英国也存在同样的联系。因为随着婴儿潮期间出生的人开始退休，受赡养人群的比例将会升高，这表明债券收益率将会走高。
这对债券投资者来说是个坏消息。但股票市场又怎么样呢？邦德指出，在股票的价格水平与人口构成之间，好像也有一种联系。“当退休人口的增长速度放慢或为负值时，股票的实际价格往往偏高，”他说。2000年的互联网泡沫破裂，恰逢高储蓄人群(中年人)占人口的比例达到顶峰。可惜随着婴儿潮一代退休并提取他们的储蓄，实际股票价格应会下跌。
这还不是低迷时期的尽头。尽管有婴儿潮一代，储蓄率一直处于低位。这是因为资产价格一直如此坚挺，只需少量储蓄就已起了很大作用。如果市场疲软，中年人将不得不增加他们的储蓄，从而减缓了需求和经济增长。
