Neuberger Berman said concentrated exposure to artificial intelligence stocks and rising Treasury yields could make diversification less dependable for investors holding both equities and high-grade bonds.
In an Oct. 5 commentary, Neuberger Berman put AI-related firms’ share of U.S. stock market value at 25% to 28% and their share of marginal risk at about 50%. Joe Amato, Neuberger Berman’s president and chief investment officer for equities, urged investors to assess how much of their portfolios depends on the AI theme.
Amato cited resilient U.S. growth, technology-led gains and AI infrastructure spending as forces lifting both stocks and Treasury yields. He said high-grade bonds could respond to some of the same forces, potentially reducing their benefit as a counterweight to equities.
Analyst Jim Bianco offered a separate measure in an Oct. 11 post discussed in earlier coverage of AI-related stock concentration. He estimated that 41 AI-related companies held 48.68% of the combined market value of S&P 500 members. His group included 29 companies directly involved in AI, eight utilities and four capital-equipment companies.
Bianco’s figure covers a different group and market universe from Neuberger Berman’s U.S. equity estimate, so the percentages are not directly comparable. In his fourth-quarter outlook, Amato remained broadly constructive on risk assets while expressing greater caution about the near term.
