President Bush will deliver his 2007 State of the Union (SOTU) address on January 23rd. My analysis of the impact of these speeches suggests that usually SOTUs have minimal market impact. But two such speeches in the last 57 years have been big market movers.

SOTU addresses seem to me like the governmental version of a human appendix. They made sense during our formative years when transportation and communication were slow. But these days -- with the Internet and cable news -- we don't need an SOTU to tell us how things are going. The fact is that each citizen's experience is so different that the state of each citizen's life varies almost daily. And, as I posted last month, Bush's 2006 SOTU was a laundry list of legislative agenda items -- most of which did not pan out.

Just as most SOTUs don't change laws, most SOTUs don't move stocks. That's the conclusion I reached after analyzing the movement of the S&P 500 a day and a week after each of the last 57 SOTUs. I found that the S&P 500 rose an average of 0.01% the day after these SOTUs and 0.26% a week after.

But this average masks some interesting exceptions. George H. W. Bush's 1991 SOTU drove the S&P 500 up 4.39% in the week after the speech during which he announced the wildly successful Desert Storm which was largely won by the end of the week. By contrast, Richard Nixon's first SOTU in 1970 -- where he announced balanced budget and anti-pollution measures -- stripped 5.08% from the S&P 500 within the week.

George W. Bush's SOTUs rank him seventh out of 11 presidents in their stock market impact. His average SOTU has cut 0.13% from the S&P 500 in the day after the speech and 0.11% in the week after.

Let's see how he does this year.

Peter Cohan is President of Peter S. Cohan & Associates, a management consulting and venture capital firm, a Professor of Management at Babson College, and editor of The Cohan Letter.