Jim O’Shaughnessy of O’Shaughnessy Asset Management.

A few excerpts:

The 40 years ending February 2009 were the second worst 40-year period for equities since 1900, with only the 40 years ending December 1941 doing worse! …

We are talking about an event so rare, that most of us alive today will never see such an opportunity again.

Many will say that I got bullish too early, writing that stocks were a screaming buy in Fall 2008 and that they have only declined since then. That’s true. Yet major stock market bottoms are seldom defined by a single point in time. Stocks began presenting great opportunities in the fall of 2008, and those opportunities have improved even more since then. Disciplined long-term investors learn to take advantage of these broad market valleys and continue putting money to work as long as the huge opportunity remains.  

Now is the time for all investors to do the same — for young investors, this is perhaps a once in a lifetime gift, and they should do their best to open and make maximum contributions to their 401(k)s and other tax advantaged plans. 

For middle-aged investors like myself, I recommend increasing the equity allocation of your portfolio to 70 percent and consistently moving money into stocks over the coming months.

And for investors who are already retired, now is the time to increase your allocation to stocks, particularly if you are significantly overweight bonds. If you are 70 years old, the actuarial tables say you will live another 13 ½ years — and a robust portfolio will help you enjoy your remaining years more fully.  

I believe that this time will be no different and that investors who take advantage of currently depressed stock prices will be delighted with the outcome five to ten years from now. 

Nothing we don’t already know, but it’s good to get a reminder that stocks have followed historical long-term trends that tend to overwhelm the shorter-term trends, such as that of the last 18 months.  

And he has some very interesting charts about 40 year returns to back up his main point.   It’s worth clicking through just to see the charts.