Warren Buffett’s simple 90/10 allocation — 90% in a low-cost S&P 500 index fund and 10% in short-term government bonds — produces roughly $4,800 a month in spendable income for a single 65-year-old with a $600,000 traditional IRA and $2,800 a month in Social Security, while the federal tax bill falls to about $1,013 for the year. The plan, detailed by 247wallst.com, applies Buffett’s 2013 advice for his wife’s trust to a retiree who must draw down principal, and the math shows the portfolio can support a 4% withdrawal rate with a cash cushion for market downturns.
The allocation puts $540,000 into Vanguard’s S&P 500 ETF (VOO), which closed Tuesday at $704.78 a share with a 1.05% dividend yield, and $60,000 into three-month Treasury bills yielding 4.21%, according to 247wallst.com. The stock portion generates about $5,670 a year in dividends and the bills about $2,530, for total portfolio income of roughly $8,200, or $683 a month, before any shares are sold.
The 4% Withdrawal Adds $2,000 a Month From the IRA
To reach the $4,800 monthly total, the retiree withdraws $24,000 a year — a standard 4% rate — from the traditional IRA, combining with the $2,800 Social Security check for $57,600 a year in cash flow, 247wallst.com reported. The $8,200 of dividends and interest covers about a third of that withdrawal, leaving $15,800 to come from selling roughly 22 shares of the index fund annually at current prices.
In a year when stocks fall, the plan shifts the entire $24,000 withdrawal to the $60,000 Treasury bill allocation, leaving the stock fund untouched to recover; that cushion covers about two and a half bad years, according to 247wallst.com. A 5% withdrawal of $2,500 a month historically holds up over 30 years, but a 6% rate of $3,000 a month has run out of money in the worst 30-year stretches on record.
Social Security Taxation and the Senior Deduction Shrink the Bill
The tax calculation produces a low bill: the IRS adds IRA withdrawals plus half of Social Security to determine taxable benefits, and for this profile — $24,000 plus half of $33,600 equals $40,800, which exceeds the $34,000 threshold for a single filer — $10,280 of the $33,600 benefit becomes taxable, leaving $23,320 tax-free, 247wallst.com reported. Total federal income is therefore $34,280.
Three deductions then apply for 2026: the $16,100 standard deduction for a single filer, a $2,050 additional amount for being 65 or older, and a new $6,000 senior deduction created by the 2025 tax law and available through 2028 to those under $75,000 in income, totaling $24,150. Subtracting that from $34,280 leaves $10,130 in taxable income, all in the 10% bracket, for a federal tax bill of about $1,013 — an effective rate under 2% on the $57,600 cash flow, according to 247wallst.com.
At 73, Required Withdrawals and Roth Conversions Change the Math
Starting at age 73, the IRS requires annual withdrawals from a traditional IRA; on an account grown to $800,000 by then, the first required minimum distribution is about $30,200, which exceeds the $24,000 the plan draws and pushes more Social Security into taxable income while raising the tax bill, 247wallst.com reported. Advisors suggest converting roughly $22,000 a year from the IRA to a Roth between ages 65 and 73, filling the lower tax brackets now rather than paying higher rates later when required withdrawals stack on top of Social Security; Roth money has no required withdrawals and comes out tax-free.
The $60,000 Cushion Carries the Risk
The plan’s stability depends on preserving the $60,000 Treasury bill allocation; spending that cushion on a large expense in year one converts the portfolio to 100% stocks with a fixed withdrawal, a riskier structure, 247wallst.com reported. The S&P 500’s 1.05% yield also means retirees who must spend from the account, unlike the widow in Buffett’s advice, will not find sufficient income from the index fund’s dividends alone.
Buffett’s 2007 Bet and VOO’s Track Record Back the Strategy
The index approach has empirical support: in 2007, Buffett wagered $1 million that a low-cost S&P 500 index fund would outperform a basket of hedge funds over 10 years after fees, and he won, FinanceBuzz reported. The Vanguard S&P 500 ETF has delivered annualized returns of 14.94% since its September 2010 inception, while the S&P 500 has averaged about 9.98% annually since 1928 and roughly 10.7% since 1957, according to The Motley Fool and Yahoo Finance.
FAQ
Does Buffett’s 90/10 rule work if a retiree must spend the principal?
Yes, for a 65-year-old with $600,000 in a traditional IRA, the 90/10 split supports a 4% withdrawal of $2,000 a month plus $2,800 in Social Security for $4,800 total monthly income, provided the $60,000 Treasury bill cushion remains intact to cover withdrawals during stock market declines, according to 247wallst.com.
How much federal tax does a retiree owe on Social Security and IRA withdrawals at 65?
A single 65-year-old withdrawing $24,000 from an IRA while collecting $33,600 in Social Security owes about $1,013 in federal tax for 2026 after the $6,000 senior deduction and other standard deductions reduce taxable income to $10,130, 247wallst.com reported.
When do required minimum distributions start on a traditional IRA?
The IRS requires the first distribution at age 73, which on an $800,000 balance would be roughly $30,200, more than the $24,000 annual withdrawal in the 90/10 plan, according to 247wallst.com.
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