The best analysis we have seen suggesting the stock market may be overvalued was a "memo" written by Howard Marks. Howard Marks (@HowardMarksBook) is co-chairman and co-founder of Oaktree Capital Management, a leading investment firm with more than $125 billion in assets under management. He is the author of the books Mastering the Market Cycle: Getting the Odds on Your Side and The Most Important Thing: Uncommon Sense for the Thoughtful Investor.

Mr. Marks is admired in the investment community for his "memos", which detail his investment strategies and insight into the economy. According to Warren Buffett, "When I see memos from Howard Marks in my mail, they're the first thing I open and read. I always learn something...."

The link to the memo is here on the Oaktree Capital Management website.