Priya's Seven-Year Bridge: ACA Subsidies, IRMAA, and the Conversion Window

For premium tax credit purposes, MAGI is AGI plus tax-exempt interest, nontaxable Social Security, and excluded foreign income. Crucially, it includes realized capital gains and Roth conversions, and excludes Roth withdrawals and return of basis. That asymmetry is the whole plan.

Illustrative year:

• Spend the $60,000 of cash (zero MAGI).
• Sell roughly $45,000 of taxable shares with a 35-40% embedded gain, generating about $16,000-$18,000 of MAGI while producing $45,000 of spendable cash.
• Fill the remaining room to the MAGI target with a Roth conversion - roughly $40,000 at a $60,000 target.

Judgment calls:

1. Build in a buffer. The credit falls off a cliff rather than phasing out gradually under the traditional structure, so a dollar of unexpected gain can cost thousands. Target $3,000-$5,000 below the line, not at it.
2. The conversion is not free. Inside the 10-12% bracket, the credit phaseout stacks an effective marginal rate on top of the statutory rate - often 20%+ combined. Convert only to the extent the all-in rate is still below her projected future rate.
3. Do not cross the cliff to convert. If she cannot both fund $105,000 and stay under the target, fund the spending from cash, basis, and Roth principal and skip the conversion. Losing a subsidy to save 12% is a bad trade.
4. Verify the current-year subsidy structure before acting. The cliff and the enhanced subsidies have been moving targets legislatively; model both outcomes and re-check annually.

The constraint changes twice.

At 65: IRMAA is based on the tax return from two years earlier - so the low MAGI she engineered at 63 also controls her Part B and Part D premiums at 65. Because she retired, she also has a life-changing event that permits an IRMAA appeal (Form SSA-44) if a later year's income would otherwise spike the premium.

From 65 to 74: this is the conversion window, and it is the last clean one. Her Social Security is not yet claimed, the ACA constraint is gone, and RMDs have not started. Her RMD age is 75, since she was born in 1962.

Size the problem before recommending anything. Left untouched, $1.5 million at a 5% growth rate reaches roughly $2.7 million by 75. A first RMD divided by the age-75 factor of about 24.6 is on the order of $100,000-$110,000 - before Social Security, before any gains, and taxed at single-filer rates permanently. That is the number that justifies conversions.

Judgment:

• Convert to the top of the 24% bracket in years when she has no other income spikes, but check each conversion against the IRMAA tier boundaries - an extra $1,000 of conversion can cost several hundred dollars in Medicare premiums, so a "fill the bracket" instruction is wrong at the margin.
• Recognize that she may be paying 22-24% to save her heirs 24% or 32% - a modest arbitrage, not a windfall. The real gain comes from reducing RMD-driven income later and from the survivor/single-filer compression she already lives with.
• Shift her $10,000 of annual giving to qualified charitable distributions once she is 70½. A QCD satisfies the RMD, is excluded from income entirely, and lowers MAGI, whereas a $10,000 itemized deduction is likely worthless to her against the standard deduction plus the age-65 addition.

Delay, with one condition.

The arithmetic: waiting from 67 to 70 raises her benefit from $36,000 to $44,600 - $8,600 a year, inflation-indexed, for life, plus a larger survivor base if she ever had a spouse on her record. That is roughly a 24% increase in exchange for three years of foregone benefits; breakeven on nominal dollars falls in the early-to-mid 80s, and because the benefit is CPI-indexed and backed by the government, it is the cheapest inflation-protected lifetime income she will ever be offered. It is also the asset that cannot be outlived or lost to a market decline.

The condition: the bridge must be funded without wrecking the conversion plan. Years 63-70 now require $105,000 a year with no Social Security. Drawing that from the traditional IRA drives MAGI up, which simultaneously costs her the ACA credit at 63-64, raises IRMAA at 65, and competes with conversions. Drawing from cash, taxable basis, and Roth principal keeps MAGI down and preserves both the subsidy and the conversion room.

So the sequencing judgment is: spend the Roth early to buy a bigger government annuity later. That feels wrong to clients who have been told to preserve the Roth for heirs, and it can be. But the Roth she spends preserved a subsidy, an IRMAA tier, and a conversion window, and it bought her a permanently higher inflation-adjusted floor. Run the comparison both ways and show her the two ending balances - in most renditions of this fact pattern, delaying and bridging from Roth wins if she lives into her mid-80s, and loses modestly if she does not. Her health and family history decide the case, not the spreadsheet.