Recent analyses indicate a growing divergence between the S&P 500's price gains and its earnings revision breadth, raising concerns about the sustainability of its earnings. Experts note that the S&P 500 currently trades at valuations significantly higher than historical averages, with some suggesting it is 60% more expensive than global stocks. This premium is attributed to the increasing ratio of corporate profits to GDP and a select group of companies enjoying global competitive advantages. However, there are warnings that the focus on forward earnings per share (EPS) projections, rather than trailing EPS realities, may leave the market vulnerable to a cyclical downturn, as highlighted by various analysts.