US equities are facing one of the most divided research debates of the cycle: bears warn of an AI bubble and stretched valuations, while bulls see a mid-cycle expansion with room to run.
On the bearish side, researchers point to the Buffett valuation metric at all-time highs, a Nasdaq 100 that swelled from $30T to $41T in under 50 trading days, and a looming $200–250B IPO wave (SpaceX, OpenAI, Anthropic) that could unlock $3T of insider selling by end-2027. Some recently published views describe the AI buildout as entering a "blow-off top," with semiconductor and hyperscaler forecasts they call physically impossible.
The bullish camp of analysts frames the US as a solid mid-cycle expansion, with one published target as high as S&P 9,000 on 2027 earnings (contingent on lower rates and easing geopolitical risk). Structural AI momentum and a resilient top-tier consumer are cited as support.
Where research converges: small and mid caps, healthcare/biotech, and energy are flagged as undervalued rotation candidates as capital potentially leaves crowded megacap tech.