Is 100% stocks brilliant or reckless? Quantified

"Is 100% stocks brilliant or reckless?" is a title that wants a winner. The freeze does not owe it one. For this already-retired specimen, raising the stock share on a rigid 4% withdrawal raises typical leftovers and lowers the share of lives that last. That is a trade-off surface, not a personality. Quantified means we print both axes.

Specimen: $1,000,000, age 65, 30 years, rigid 4%, seed 20260622, 1,000 paths. Mixes: stocks 40% to 100% in 10-point steps, remainder in bonds, cash 0, plus the B4 default 80/15/5 as a named point. Constant-mix, rebalanced. Pairing by seed.

100% stocks, quantified

Success at 40% stocks: 96.4%. At 60%: 93.9%. At 80%: 89.3%. At 100%: 83.6%. The line falls. A 100% stock mix is not the mix that maximises the last-or-not meter on this retiree. It is the mix that maximises the right tail: p95 at 100% is $12,381,810 against $5,323,302 at 60/40.

Median terminal at 40% stocks: $816,332. At 60%: $945,221. At 80%: $1,062,386. At 100%: $1,108,144. The median climbs while success falls. p5 is already $0 from 60% stocks up. The left tail is a floor. 40% stocks still has a positive p5 ($46,833). That is the quantified split: more stocks, kinder typical ending, fatter chance the ending is zero.

The 80/15/5 specimen point prints 89.6% success and $1,083,603 median, next to 80/20's 89.3% and $1,062,386. Five percent cash is not a different life on this table. It is a small move along the same slope.

Brilliant and reckless are both incomplete

Brilliant would have required 100% stocks to raise success, or to raise p10, without a matching hole somewhere else we care about. It raised the median and p95. It did not raise success. Reckless would have required a collapse. 83.6% of lives still last. That is not a collapse. It is a worse last-or-not print than 60/40 on this retiree, with a better typical leftover. If your primary is ruin, 100% is the costlier mix here. If your primary is median bequest, it is the cheaper mix. The card forbade crowning either word.

Leverage is not in this study. 100% stocks is not 1.5×. The long-term leverage article on this site is a different domain (a constant overlay on a tape). Do not import its surface here. Do not import this surface there.

Accumulation is not in this study. A 35-year-old saving $3,000/mo has a different horizon and a different ruin definition. This freeze is a retiree taking 4% from a million. Repeating "100% stocks for the young" from this table would be a domain mix-up.

Q2, and what was not run

Stock mu minus 0.02. 100% stocks success: 71.0%. 60/40: 85.7%. 60/40 remains higher on success. The shave did not make 100% the safer last-or-not mix. Medians both fall (100% $383,172, 60/40 $528,081). A lower premium hurts the stock-heavy mix more on the typical leftover too, in this sample.

Q3 not run. Not a historical 100% versus 60/40 claim. 1966 and 2000–02 as 30-year retirements would be a veto we did not take. Q4 not a 0-versus-5-bps stress. Rebalance turnover is on at 5 bps for every mix, including 100% stocks (which has less to rebalance). Gross of a true 0-bps comparison. Tax off. No leverage, no sequence of jobs.

What would falsify a split reading: 100% stocks worse on both success and p10 than 60/40 with no median gain, or the mu-shave flipping success in favor of 100% while a title still said reckless. The freeze kept the split. The title kept "quantified."

The grid, not the slogan

50% stocks: success 95.1%, median $906,321, p95 $4,308,731. 70% stocks: success 92.0%, median $1,013,594. 90% stocks: success 86.5%, median $1,089,784, p95 $9,975,610. Each step along the stock share buys some median and some p95, and spends some success. There is no step where both meters rise.

40% stocks still prints a positive p5 ($46,833) and 96.4% success. That is the left end of the grid, not a recommendation. A 0% stock mix was not on the card. Adding it after seeing 40% would have been search. We did not add it.

The Q2 medians ($383,172 at 100% stocks, $528,081 at 60/40) show that a lower premium compresses leftovers for both mixes and still leaves 60/40 ahead on last-or-not. If someone wants to call 100% stocks brilliant, they need a different primary than success on this retiree, and they need to say so. If they want to call it reckless, they need to explain why 83.6% lasting is reckless. The freeze will not say either word for them.

See a mix as two meters

The demo will let you move allocation and reread success and a cone. That pairing is the whole article. The guardrails calculator is a different axis (spending flexibility), not a substitute for mix. If you only watch the median ending climb from $945,221 at 60/40 to $1,108,144 at 100% stocks, you will call the move brilliant. If you only watch success fall from 93.9% to 83.6%, you will call it reckless. This freeze printed both, on purpose, so that neither word could survive as a ranking. Quantified means the two-column table. Anything shorter is a slogan.

80/15/5 sits next to 80/20: 89.6% versus 89.3%, $1,083,603 versus $1,062,386. Cash at 5% is not a third philosophy on this retiree. It is a small step on the same slope. Do not build a product identity on a 1-point success gap that is inside a 1-point standard error anyway.

What this page refuses to say

It refuses brilliant. 100% stocks did not raise success. It refuses reckless. 83.6% of lives still last. It refuses a young-saver caption. This is a retiree taking 4% from a million. It refuses a leverage caption. 100% is not 1.5×. It refuses to add 0% stocks or 95% stocks after seeing the slope. It refuses to let p95 of $12,381,810 answer a ruin question. It refuses to let 93.9% at 60/40 answer a bequest question.

It refuses a historical 100% versus 60/40 probability. Q3 was not run. 1966 as a 30-year 100% stock retirement is a veto we did not take. It refuses to treat 5 bps as a full cost study. 100% stocks rebalances less. Gross of a 0-bps comparison. Tax off. It refuses Sharpe as a primary. Sharpe was not on the card.

It refuses a one-word answer to the title. The title is a search query. The freeze is a split. If a later writer wants a winner, they need a different primary, a different household, or a different horizon, and they need a new card dated before that run. This card is closed.

Q2: 100% stocks success 71.0% versus 60/40 85.7%. The shave did not crown 100% on last-or-not. If anything it widened the success gap against 100%. That is allowed to be the Q2 sentence. It is not allowed to become "so never hold stocks." 40% stocks is still on the grid and still has a median of $816,332.

Replication spec

B4_RETIREE, rigid 4%, seed 20260622, 1,000 paths per mix. Mixes cash/stocks/bonds: 0/40/60, 0/50/50, 0/60/40, 0/70/30, 0/80/20, 0/90/10, 0/100/0, plus 5/80/15. Static rebalance. Success, p5, p50, p95 from the engine summary on the rigid_4 agent.

40% stocks: 96.4% / p5 $46,833 / p50 $816,332 / p95 $3,360,932. 50%: 95.1% / $906,321. 60%: 93.9% / $945,221 / p95 $5,323,302. 70%: 92.0% / $1,013,594. 80%: 89.3% / $1,062,386. 90%: 86.5% / $1,089,784 / p95 $9,975,610. 100%: 83.6% / $1,108,144 / p95 $12,381,810. 80/15/5: 89.6% / $1,083,603.

Q2: 100% stocks 71.0% median $383,172; 60/40 85.7% median $528,081. Success order unchanged (60/40 higher). CSV: /data/studies/100-percent-stocks-quantified.csv. Q3 not run. Q4: 5 bps, tax off, no leverage. Search budget 0: we did not add 95% or 0% after seeing the slope.

The title asks brilliant or reckless. The freeze answers with two columns. Median up, success down, as stock share rises, on this retiree, on this rate, on this seed. That is the quantified result. A different household would need a different card.

Last recap: rigid 4% retiree, stock share 40 to 100. Success falls from 96.4% to 83.6%. Median rises from $816,332 to $1,108,144. 60/40 versus 100%: 93.9% and $945,221 versus 83.6% and $1,108,144. Q2 keeps 60/40 ahead on success (85.7% versus 71.0%). Brilliant does not survive. Reckless does not survive. Quantified survives. Not a historical claim. Not leverage. Not a 35-year-old saver. New card required if you want any of those.

80/15/5 is 89.6% and $1,083,603, a neighbor of 80/20, not a third religion. Seed 20260622. 1,000 paths per mix. Search budget zero. p5 is zero from 60% stocks upward on this retiree, so the left tail is a floor, not a thin scrape. 40% stocks still shows a positive p5 of $46,833. That is the last column worth keeping next to success and the median: whether the fifth percentile is already the account at zero. 100% stocks does not win that column. 60/40 does not win the median. The split is the table. The table is the article. If a mix is added to the CSV without a new card, the study is void. The grid was the budget. We spent it. Do not add 95 percent stocks to flatter a slope. Do not crown a winner. Print success and the median together, or print neither. Read the freeze file. Seed 20260622. Stop now.

Notes. B4_RETIREE, rigid 4%, seed 20260622, 1,000 paths. Stock share 0.40 to 1.00 step 0.10, rest bonds, plus 80/15/5. Static rebalance. Q1 run. Q2 run on 1.00 versus 0.60 with stock mu −0.02. Q3 not run. Q4: 5 bps, tax off, no leverage. CSV: /data/studies/100-percent-stocks-quantified.csv. Card dated 2026-08-28. This article is educational analysis, not investment advice, and does not recommend any security or strategy.