Ian Smith in London and George Steer in New York
US equities have soared to their most expensive level relative to government bonds in a generation, amid growing nervousness among some investors over high valuations of megacap technology companies and other Wall Street stocks.
A record-breaking run for US equities, which hit a fresh high on Wednesday, has pushed the so-called forward earnings yield — expected profits as a percentage of stock prices — on the S&P 500 index