I'm pessimistic about the SPX - there is a good chart that's in Schillers book where the inverse of PE at the beginning of each decade is plotted against next 10 yr returns. The plots from history all point towards a strong positive relationship - the higher a PE you start out with at the beginning of each decade, the lower the market returns.
Collapsing multiples will outpace rising corporate earnings from GDP growth played out over the rest of the decade. To use some easy math - if multiples collapse from say 20x to 15x over the next 10 years, earnings have to grow steadily at 5.25% JUST to keep the S&P flat at 1020 in the year 2014.
I am, however, optimistic about US GDP growth. I think we will look back in 2010 and everyone will have realized how much they underestimated the positive impact it had on productivity.
The amount of data about the US that is available out there on the net far far outstrips that of any other country. That makes every person in the US that much more knowledgable about the society and market they operate in, something that is tremendously valuable and will translate into GDP growth.
What does this mean for our P&L .... well nothing really if you a trader. But plenty if you are an investor
Actually, I think that if this scenario does play out, there will be some interesting structural changes to the investment world
1) Slow death of the cult of equity (money will move out of mutuals, just like they did in the 1970s. Interestingly the rest of the world calls mutual funds unit trusts. The US dropped the monicker unit trusts because the public got so disenchanted with them that they had to rebrand themselves)
2) Increase in asset allocation towards alternative investments & foreign mkts (asset bubble somewhere else? also, overcrowding of money into hedge funds will cause traditional strategies to dry up, such as convert arb, risk arb, stat arb etc)
Since mutual funds trade mainly end of day whereas the distribution of trading by hedge funds are not so clustered, trading volume might migrate from the closing hour to the rest of the day as assets shift away from mutuals and into hedge funds.
Well , that's what my crystal ball tells me. Would love to hear from others!