AI Portfolio Recommendations Fail to Account for Expense Ratios and Global Market Cap
RF
Rowan Fairfax
index fund expense ratio · Apr 11, 2026
Source: The Digital Ledger Data Terminal
A 0.05% difference in expense ratios compounds significantly over decades. This cost reduction is why Thomas Brock, a chartered financial analyst and certified public accountant, recommended switching from the SPDR Gold Shares (GLD) fund to the lower-cost GLDM alternative for gold exposure.
ChatGPT recommended a growth-focused portfolio for a 40-year-old investor with 20 to 25 years until retirement. The AI chatbot suggested 50% U.S. stocks via the Vanguard Total Stock Market ETF (VTI), 20% international stocks via the Vanguard Total International Stock ETF (VXUS), and 20% bonds using the Vanguard Total Bond Market ETF (BND) or iShares Core U.S. Aggregate Bond ETF (AGG). It also suggested 5% real estate via the Vanguard Real Estate ETF (VNQ) and 5% gold via GLD.
Brock identified the AI's allocation as light on growth. He recommended increasing the total stock allocation to 80% to better approximate the global distribution of publicly-traded stocks, which consists of approximately 60% U.S. stocks and 40% international stocks. To facilitate this, Brock suggested reducing the bond allocation.
Brock eliminated the 5% real estate allocation to VNQ, arguing that a portfolio with 80% global stocks already contains embedded real estate assets.
Beyond the AI's asset allocation, Brock added a 2.5% liquidity reserve in a competitive money market mutual fund yielding 3.5% to 4.0%.
index fund expense ratio
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