In a paper published earlier this month, GMO’s James Montier argues that the stock market is in the grip of a “cynical bubble,” according to an article in Bloomberg.

Montier doesn’t share the optimism of his colleague, Jeremy Grantham, who recently expressed his view that the market could be headed for a late bubble “melt-up” the article says. In the paper, Montier writes, “Those buying the asset in question don’t really believe they are buying at a fair price, but rather are buying because they want to sell to someone else at an even higher price before the bubble bursts.”

He cites Shiller P/E ratio data that shows how U.S. stocks are at the second most expensive level in history.