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Decumulation Studio

Joint Roth conversion and withdrawal-sequencing optimizer under bracket, IRMAA, ACA, LTCG, NIIT, RMD, and Roth 5-year-clock constraints.

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What It Does

The Decumulation Studio searches a joint schedule of Roth conversions and account-by-account withdrawals against a user-selected objective (fill a bracket, stay below an tier, maximize real terminal wealth, maximize lifetime ACA premium tax credits, or minimize lifetime tax present value). It evaluates the proposed schedule alongside a baseline (no-conversion, naive sequencing) so the tradeoff is explicit.

Features

  • Joint conversion and withdrawal schedule by year and account.
  • Pluggable objectives covering bracket fill, IRMAA ceiling, ACA credit maximization, lifetime tax PV, and real terminal wealth.
  • Per-year multi-cliff explainer: which constraint set bound the optimizer in each year.
  • Marginal-cost surface that quantifies how much each extra dollar of conversion or withdrawal would cost across years.
  • Year-drill decomposition showing the ordinary marginal, , LTCG bump, ACA, IRMAA, and state-tax components of the marginal dollar.

When To Use It

  • Evaluate decumulation strategies after retirement when conversions and withdrawals interact with Social Security taxation, Medicare IRMAA, ACA subsidy cliffs, RMDs, and Roth 5-year clocks.
  • Compare withdrawal orderings (taxable-first, traditional-first, Roth-last) under the same household, return, and inflation assumptions.
  • Stress-test a planned schedule against bracket and IRMAA caps and see which years approach which cliffs.

Open the Decumulation Studio

Pick a household, set the plan horizon and spending, choose an objective, and inspect the proposed schedule alongside a no-conversion baseline.

Pro workflow
Open Decumulation StudioSee plans
What each plan includes, tool by tool

Main Inputs

  • Plan anchor: start year and horizon years. Every dated rule (, IRMAA y-2 lookback, ACA regime) resolves from the start year.
  • Household: the selected household supplies members, accounts, filing status, resident state, ACA inputs, and prior IRMAA history.
  • Assumptions: nominal asset return, inflation rate, and real annual spending.
  • Objective: bracket fill, IRMAA tier ceiling, lifetime ACA , lifetime tax present value, or real terminal wealth.
  • Withdrawal policy: taxable-first, traditional-first, or Roth-last sequencing.
  • Constraint caps: ordinary bracket cap, optional IRMAA tier ceiling, optional LTCG 0% preservation, and optional NIIT prevention.

How To Interpret Results

  • Action schedule: conversion and withdrawal amounts by year and account.
  • Binding-constraint rows: the cliff or cap that bound each year for the proposed schedule and the baseline.
  • Marginal surface: dollar-by-dollar cost of additional conversion or withdrawal pressure across the horizon.
  • Year drill: ordinary marginal, LTCG bump, NIIT delta, IRMAA delta (y+2), ACA delta, and state marginal for a chosen year.

Known Scope

  • Saved analyses for this tool are private-only. Generic public share links are not registered for Decumulation Studio runs.
  • ACA FPL modeling supports contiguous states/DC, Alaska, and Hawaii poverty-guideline tables.
  • The optimizer is a bracket-fill heuristic plus a marginal-cost search. It is not a stochastic or globally optimal solver.

Cliff Vocabulary

Glossary

MAGI (Modified Adjusted Gross Income)
AGI with certain items added back. Each cliff uses its own MAGI definition: NIIT, IRMAA, and ACA subsidies are computed on different bases, so one conversion can sit at different distances from each cliff.
IRMAA y-2 lookback
Medicare premium surcharges in a given year are set by your MAGI from two years earlier. A conversion this year raises premiums two years from now, which is why results show IRMAA deltas at y+2.
ACA Premium Tax Credit (PTC)
The subsidy that lowers marketplace health-insurance premiums, based on household income relative to the federal poverty level. Conversions raise income and can shrink or eliminate the credit.
FPL (Federal Poverty Level)
The income benchmark, scaled by household size, that ACA thresholds are expressed against (for example 400% of FPL).
SLCSP (Second-Lowest-Cost Silver Plan)
The benchmark marketplace plan premium used to compute the ACA credit. The planners need its premium to value subsidy loss in dollars.
Roth 5-year clock
Each conversion starts a five-year waiting period before that amount can be withdrawn penalty-free (before age 59 1/2). The planners track a clock per conversion year.