A financial planner reviewed a ChatGPT-generated retirement plan for a $200,000 annual income. ChatGPT used the 4% Rule, calculating that $200,000 divided by 4% equals $5 million needed. It outlined a three-bucket strategy with two years of cash ($400,000) and five years of bonds ($1 million). Thomas J. Brock, a CFA and CPA with over 25 years of experience, said the $5 million target understates the real need because ChatGPT did not account for taxes in the core calculation. Brock noted that if the effective tax rate is 25% and you need $200,000 to spend, the correct formula is ($200,000 ÷ (1 - 0.25)) ÷ 0.04 = $6,666,667, a $1.67 million difference. Using a conservative 3.5% withdrawal rate, ChatGPT's formula gives $200,000 ÷ 0.035 = $5,714,286 needed, while Brock's formula gives ($200,000 ÷ (1 — 0.25)) ÷ 0.035 = $7,619,048 needed, an almost $2 million difference. Brock warned that hitting $5 million and retiring could lead to stress as withdrawals spike the tax bracket and Medicare premiums jump.