Memories of the “frothy” markets of 2000 and 2007 is tempering investors’ enthusiasm, according to The Wall Street Journal. “After an eight-year bull market and the cheapest borrowing costs in history,” the article says, “the big surprise isn’t that the stock market’s high, but that it isn’t higher still.”

While suggesting that “mini-bubbles have been appearing,” the article says this isn’t leading to investors to “getting carried away and mispricing risks across the market.” It adds that consumer sentiment is positive and that, based on PE, price-book and price-sales ratios, valuations have “rarely been pricier.”

Bonds (Treasuries, corporate and junk) are also expensive, it says, and neither political nor geo-political uncertainties seem to be tempering pricing. The article expresses some concern about this apparent complacency, particularly given the potential for inflation and further “Fed tightening.” It suggests that investors should keep an eye out for “the story that will turn the stock price boom into a proper bubble, and inflate prices and valuations still further.”