The valuation on the S&P 500 is now almost in the 20% most expensive of all time. History shows that now is not the time to be chasing the excessive price. The two sectors that are the most expensive are technology and consumer discretionary — they have only been as expensive as they are today 15% of the time in the past. Even financials have been cheaper 70% of the time in the past relative to where they trade today, even including this year’s drubbing. By far the cheapest sectors in terms of current valuations benchmarked against their past are...