Wall Street analysts warn that tech earnings bubble threatens the classic 60/40 mix

Goldman Sachs’ chief global equity strategist Peter Oppenheimer warned that while valuations may appear reasonable, the technology sector is likely riding an earnings bubble, a view echoed by Apollo’s chief economist Torsten Slok, who declared the long-standing 60/40 portfolio framework broken. Their assessments follow a week of dramatic swings in big-tech results, highlighted by Microsoft’s 17% share surge that added nearly $500 billion in market value in a single day.

Slok’s concerns stem from a slowdown in AI-related spending, rising government debt projected at 175% of GDP, and a yield-curve environment that undermines both equity and bond returns. Oppenheimer pointed to broader market participation, noting that the equal-weighted S&P 500 has outperformed the cap-weighted index for the first time since 2009, as hyperscaler capex pressures erode their cash-flow premiums. Earlier warnings from industry veterans like Jamie Dimon, Ray Dalio and BCA Research’s Peter Berezin warned of over-optimism and an earnings-driven bubble, foreshadowing recent sharp drops such as IBM’s 25% plunge. Together, these signals suggest that the investment landscape that relied on low rates and tech concentration may be entering a new, less predictable regime.