SIS vs SPIA — Why a Structured Installment Sale Is Not a Lifetime Annuity

⚠ Important — Read first

An SIS is NOT a lifetime-guaranteed annuity. It is period-certain only.

The Structured Installment Sale annuity runs for a fixed term selected at issuance — typically 5, 10, 15, 20, 25, 30, or 40 years — with payments scheduled in advance and printed on the contract. There is no lifetime-payment option in the SIS structure. If you outlive the term, the payments end. If you die before the term ends, the remaining payments continue to your designated beneficiary (whom you can change at any time during the term).

Death is an uncertain deadline — and the IRS needs a known schedule. §453 works by computing a "gross profit ratio" (the share of each payment that represents recognized gain) and applying it to each scheduled payment as you receive it. To do that, the IRS needs to know how many payments will be made and on what dates. A pure life-contingent annuity has an indeterminate end date — mortality — so the gross-profit-ratio math can't be cleanly applied to a §453 obligation. Worse, the IRS would likely treat receipt of a life-contingent annuity at closing as receipt of property at fair market value under §1001, meaning the full gain is recognized in Year 1 and the §453 deferral collapses entirely. (Treas. Reg. §15a.453-1(c) does contain a contingent-payment installment-sale framework, but the rules are complex, front-load basis recovery, and the structured-settlement industry has standardized on period-certain because the audit risk and complexity make life-contingent structures impractical.)

Period-certain payments are what make the tax structure work. Every SIS is issued as a fixed-term annuity (5–40 years) with a printed schedule of payment dates and dollar amounts on the contract. The IRS can compute the gross profit ratio in advance, the carrier knows exactly what it owes and when, and there's no mortality math in the way.

Plan accordingly. The SIS is a bracket-compression tool for the proceeds of a specific sale — not a lifetime income guarantee. If lifetime income is the goal, pair the SIS with a separate SPIA or DIA from your cash carve-out at closing. (See /myga-option/ for cash-side product options.)

Product category

And it's a plain fixed annuity — not variable, not indexed.

An SIS is funded by a fixed annuity — the most conservative annuity category. Fixed means the dollar amount of every scheduled payment is contractually guaranteed by the carrier. There's no market exposure, no sub-account selection, no index-credit formula, no participation rate. The carrier prices the schedule once at issuance using its internal credit rate (currently in the ~4.5–5.0% range on a 25-year period-certain structure) and prints the exact payment schedule on the contract. Whatever happens to interest rates, the S&P 500, or the carrier's investment portfolio after issuance, your payments stay exactly as scheduled.

This is the same product structure personal-injury claimants have been receiving for 40+ years under the Periodic Payment Settlement Act of 1982 — a plain vanilla period-certain fixed annuity from a top-rated life carrier, paying the schedule on the contract until the term ends. No variable annuity, no indexed annuity, no MYGA wrapper. The most boring annuity category — which is exactly what makes the §453 tax treatment work and exactly what makes the income stream predictable.

▸ The side-by-side

Both use an annuity. Everything else is different.

	SPIA (Single Premium Immediate Annuity)	SIS (Structured Installment Sale)
Purpose	Convert a lump sum of money into a guaranteed income stream.	Defer capital-gains tax on the sale of an appreciated asset, using IRC §453.
Payment term	Two flavors: lifetime (single or joint, often with a period-certain rider) or pure period-certain in standard rate-card increments (typically 5, 10, 15, 20, 25, 30 years). Sold from a published rate card.	Period-certain only — but custom-quoted. Any term: 7, 11, 13, 17, 23 years. Level or stepped payments, deferred starts, balloon years, COLAs — all quotable on the same contract. No lifetime option (mortality contingency would disqualify §453 treatment).
Who funds it	The purchaser pays the premium directly to the carrier with after-tax money.	The buyer of your asset pays an assignment company (a subsidiary of the carrier writing your annuity), which funds the annuity from the sale proceeds (pre-tax, under §453).
Tax authority	IRC §72 — annuity contract exclusion ratio.	IRC §453 — installment sale gross-profit ratio + §483/§1274 imputed interest.
Per-payment tax mechanics	§72 exclusion ratio. Each payment = (investment / expected return) is tax-free return of principal; the rest is taxed as ordinary income (the implicit interest baked into the annuity).	§453 gross profit ratio + §483 imputed interest. Each payment is split twice: §483 carves off the imputed-interest portion (ordinary income), then the gross profit ratio splits the remaining principal into recognized gain (LTCG) and basis return / §121-excluded gain (tax-free).
Source of premium	After-tax money — you already paid tax on the principal you're handing the carrier.	Pre-tax sale proceeds — the buyer's payment for your asset funds the annuity before tax is recognized. This is the bracket-compression mechanism.
Mortality pricing	Yes — payout rate priced on life expectancy.	No — payout is purely time-value-of-money on a known term.
Surrender / commutation	Generally surrenderable (with surrender charge); some SPIAs are non-commutable.	Non-commutable, non-assignable by the payee. Required by §453 to preserve installment treatment.
At death	Carrier keeps the balance (pure life SPIA). Adding a cash-refund or period-certain rider softens it, but every rider drops the payout rate. Mortality-pooled pricing means long-lived annuitants are funded by short-lived ones.	Beneficiary keeps the balance. Remaining scheduled payments pass to your designated beneficiary (spouse, kids, trust, charity) at the same dollar amount, on the same dates. Nothing reverts to the carrier. Beneficiary designation is revocable during your lifetime.

Common question

“Isn't there an exclusion ratio in the SIS too?”

Mechanically, a SIS acts a lot like a period-certain SPIA. The annuity from the carrier feels the same to you: fixed dollar payments on a fixed schedule, no market exposure, no riders to wrestle with. The IRS just taxes it under a different code section — §453 instead of §72 — because it's funded by your sale proceeds before tax, not by after-tax money you handed the carrier.

So yes — there's an analogous concept, but it's called the gross profit ratio under §453, not the exclusion ratio under §72. Both do similar work: each carrier payment is split into a tax-free principal-return portion and a taxable portion. Three real differences:

Statutory home. §72 governs annuity contracts. §453 governs installment sales of property. Different code section, different reporting (Form 6252 for §453, Form 1099-R for §72).
Character of the taxable portion. SPIA exclusion-ratio taxable portion = ordinary income. SIS gross-profit-ratio taxable portion = the character of the underlying gain — long-term capital gain when the sale was of real estate or business stock held > 1 year.
Interest treatment. §72 bakes interest into the exclusion ratio — the taxable share of each payment IS the implicit interest. §453 separates interest under §483/§1274: a portion of each payment is reclassified as imputed interest (ordinary rates), and the gross profit ratio is then applied to whatever's left.

So an SIS payment is calculated in two steps: first §483 carves off the imputed-interest piece (ordinary rates); then the gross profit ratio splits the remaining principal into recognized gain (LTCG rates) and tax-free basis return (plus §121-excluded gain if applicable). The carrier's 1099 reports each component separately so your CPA posts them to the correct lines on Form 6252.

▸ Custom-quoted, not off-the-shelf

A retail SPIA is sold from a rate card. An SIS annuity is engineered to your cash-flow plan.

This is one of the most under-appreciated advantages of the structure. A period-certain SPIA at your local insurance agent is priced off a published rate card — pick "20-year period certain" and the carrier prints the rate. The structured-settlement annuity that funds an SIS is custom-quoted: the broker tells the carrier exactly what schedule you want, and the carrier prices it. Then it's reduced to a single fixed contract at closing.

That means an SIS can be shaped to your actual life, not a marketing-friendly round number:

Odd term lengths. Want 7 years to bridge to Social Security at age 70? 11 years until your spouse hits Medicare? 13 years to your kid's college tuition window? 23 years because that's when the youngest grandchild graduates? All quotable. No need to round up or down.
Stepped payments. Lower payments in years 1–5 while you're still working, larger payments in years 6–15 after retirement. Annual COLA-style step-ups (e.g., 3%/year). Front-loaded payments for a transition period.
Balloon / lump-sum years. A $400K balloon in year 10 to fund a primary-residence purchase, then back to the level monthly schedule. A college tuition lump in years 14–17. A wedding fund payment in year 6.
Deferred starts. Payments don't begin for 1, 2, 5, or 10 years — useful if you already have other income near-term and want the SIS to backstop later years.

The carrier prices the schedule using its published structured-settlement rates and standard actuarial discounting. The resulting internal rate of return on a custom-quoted SIS schedule is competitive with — and often equal to — a period-certain SPIA of similar duration from the same carrier. You're not paying a flexibility premium; you're just getting a contract shaped to your actual needs instead of a rate-card preset.

▸ “Should I pair the SIS with a SPIA for lifetime income?”

For most sellers — no. A 40-year SIS with a deferred start covers it, and your beneficiary keeps the balance.

A common follow-up question is whether to pair the SIS with a separate SPIA to lock in “lifetime income.” For most sellers, the answer is no — the SIS already covers it.

An SIS can be quoted for up to 40 years with a deferred start date of 1–10+ years after closing. A 65-year-old who structures a 40-year SIS with a 5-year deferred start receives monthly payments from age 70 through age 110 — past actuarial life expectancy. For someone retiring in their 60s or 70s, that schedule effectively covers life the same way a lifetime SPIA would.

And it does one thing the SPIA can't: when you die, the remaining payments go to your beneficiary.

SPIA (pure life): payments stop the day you die. The carrier keeps the balance — it goes back into the pool to fund payments to long-lived annuitants. This is how mortality-pooled pricing works. You can add a cash-refund or 10-year-certain rider to soften the loss, but every rider drops your payout rate.
SIS: remaining scheduled payments continue to your designated beneficiary (spouse, kids, trust, charity) at the same dollar amount, on the same dates, until the term ends. Nothing reverts to the carrier. The beneficiary inherits the income stream as IRD under §691, with the §691(c) deduction available for any estate tax paid on the remaining payments' present value.

The honest trade-off: a pure life SPIA is mortality-priced, so on a payment-for-payment basis the SPIA's rate is slightly higher than a period-certain annuity of equal length. The carrier is willing to pay you more per month because they keep what's left if you die early. The SIS converts that mortality credit into the death-benefit-to-beneficiary feature instead. For most sellers with heirs, that's the better trade.

Where a SPIA still makes sense: if longevity is the dominant concern and you genuinely have no heirs you'd want to leave the income stream to, a pure life SPIA from part of the cash carve-out can be worth the mortality cost. Otherwise, a 40-year SIS with a deferred start covers the same lifetime-income need without forfeiting the leftover to the carrier.

▸ The tax math — what's actually in each SIS payment

Every SIS payment is split into pieces. Most of it isn't taxable. The taxable part is at long-term capital-gain rates.

The IRS doesn't tax an SIS payment as one lump number. It splits each payment into legally distinct components — and each component is taxed differently (or not at all). The carrier's annual 1099 from the obligor reports each piece separately, and your CPA reports them on Form 6252.

Worked example. $3,000,000 home sale, basis $800,000, MFJ, primary residence. After §121 excludes $500K of gain, the recognized gain is $1,700,000 and the basis recovery is $800K. Sale is structured 100% into a 25-year SIS at a fictitious 4.5% carrier credit rate, producing roughly $200,000/year in scheduled payments. Each year's $200K payment is taxed as follows:

Sale Details

$3,000,000

Sale price · $800K basis · $2.2M gain · MFJ

Annual SIS Payment

~$200,000

25-year term at ~4.5% carrier credit rate

Return of basis
~$32K (16%)

§121 excluded
~$20K (10%)

Recognized gain
~$68K (34%)

Imputed interest
~$80K (40%)

Return of basis · ~$32K
Tax-free. You already paid for these dollars. Gross-profit ratio principle.

§121 excluded gain · ~$20K
Tax-free. Your $500K §121 exclusion spread proportionally across each payment.

Recognized gain · ~$68K
Taxed at long-term capital-gain rates (0/15/20% + NIIT). Spread over 25 years keeps you in lower brackets.

Imputed interest · ~$80K
Taxed as ordinary income at your marginal rate. §483 unstated-interest rule.

Result on a $200K annual payment (averaged across the term): ~$52K is fully tax-free ($32K basis + $20K §121). ~$68K of gain is taxed at LTCG rates ~15–20% ≈ $10–14K tax. ~$80K of imputed interest is taxed at ordinary rates ~30–40% (federal + CA combined for a typical California top-bracket seller) ≈ $24–32K tax. Total annual tax ≈ $35–45K on a $200K payment — a blended effective rate of ~18–22% on the payment dollars.

Important nuance — front-loading. The interest portion of any amortizing annuity is heavily front-loaded. Year-1 interest is ~$135K (the full 4.5% on $3M principal). Year-25 interest is near zero. So early years carry a higher effective rate than late years; the 18–22% figure is the average across the whole term, not what you owe in any single year.

The fair apples-to-apples comparison. The 18–22% above is the tax rate on each payment dollar (which is part basis return, part §121, part gain, part interest). A cash sale at $3M with $800K basis and $500K §121 produces ~$640K of total tax — an effective rate of ~21% on the sale total. So SIS saves ~1–3 percentage points of effective per-dollar tax, plus the substantial benefits below.

Where the SIS savings actually come from. Total nominal tax over 25 years (~$875K–$1.125M) is close to or modestly higher than the cash-sale nominal tax (~$640K). The real benefits are structural, not nominal:

Time value of money on a 25-year deferral — the present value of $35–45K/yr × 25 yrs at a 4% discount is meaningfully less than $640K paid in Year 1.
Compounding the full pre-tax principal ($3M) inside the carrier annuity vs the after-tax remainder ($2.36M) outside.
NIIT cliff avoidance — 3.8% × $1.7M = $64K saved in years where SIS payments stay under the threshold.
IRMAA cliff avoidance — ~$8–10K/yr × 2 yrs of Medicare-premium surcharge avoided.
MHST cliff avoidance on each year's payment ($1M MFJ threshold) — ~$7K saved.
Bracket compression — keeping the gain in 15% LTCG vs 20% + NIIT each year.

Add it up and the typical California seller permanently saves ~$150K–$250K net-of-tax with SIS vs the cash-sale path — not by paying less total nominal tax, but by paying it later, in smaller pieces, and avoiding the cliff taxes that hit you only when income spikes.

All numbers are illustrative ballparks for educational purposes only. Your actual split depends on the carrier-supplied gross-profit ratio, the imputed-interest rate (AFR-based), your marginal brackets, NIIT applicability, state tax, MHST/IRMAA exposure, and the specific term/structure of the annuity. The carrier's 1099 reports each component; your CPA does the actual tax return.

Why this beats “cash sale, then buy a SPIA.”

On a payment-for-payment basis, a 25-year period-certain SPIA and a 25-year SIS look similar in shape — both split each payment into a tax-free return-of-principal component and a taxable component. The mechanics are conceptually close. So why doesn't “cash sale + SPIA” produce the same end result?

Two reasons, both about the principal you're working with:

You pay the full Year-1 capital-gains bill before you start. On a $3M California sale with $2.2M of gain, that's $700K+ of tax handed to the IRS and FTB in April. You buy the SPIA with the after-tax remainder — ~$2.3M, not the full $3M. The SPIA can only annuitize the money you actually have.
The SPIA's taxable component is ordinary income. The exclusion-ratio split is mechanically similar to SIS, but on the taxable side, SPIA gain is ordinary income (up to 37% federal). SIS gain stays at long-term capital-gain rates (15–20% + NIIT) because §453 preserves the character of the original gain.

In the SIS structure, the full pre-tax sale price funds the annuity, the recognized gain is recognized over 5–40 years instead of all in Year 1, and the gain stays at LTCG rates throughout. Same A-rated carrier. Same fixed-period-certain annuity contract shape. Different statutory authority — and a 30–40% better net-of-tax outcome at the end of the schedule because of those two principal-side facts.

▸ Annuity types — one paragraph each

Where SIS sits in the broader annuity landscape.

"Annuity" is a contract type, not a single product. The major categories below all use an insurance carrier as the obligor and a regulated reserve framework, but they serve different purposes. SIS is a specialized application of the fixed-period-certain category — not the same animal as the others.

SIS

Structured Installment Sale

A fixed period-certain annuity funded directly from sale proceeds of an appreciated asset (real estate or a business), under IRC §453. Period 5–40 years. Non-commutable. The vehicle this site is about.

Tax: §453 gross-profit-ratio + §483 imputed interest. Gain portion at LTCG rates.

SPIA

Single Premium Immediate Annuity

You hand a carrier a lump sum of after-tax money; they begin paying you a stream of income immediately (or within 12 months). Most commonly lifetime payments with optional period-certain rider. Used to convert savings into guaranteed retirement income.

Tax: §72 exclusion ratio. Interest portion at ordinary income rates.

DIA

Deferred Income Annuity (Longevity Annuity)

You hand the carrier a premium today; payments start at a future date you choose (e.g., age 80 or 85). Used to hedge longevity risk — guarantees income later in life when other retirement assets may have run down.

Tax: §72 exclusion ratio when payments begin.

MYGA

Multi-Year Guaranteed Annuity

A CD-like accumulation product — fixed interest rate for a set term (typically 3, 5, 7, or 10 years), with surrender penalties during the term. Used for cash-side yield above what a HYSA pays, with tax deferral until withdrawal.

Tax: deferred during accumulation; withdrawals taxed as ordinary income (LIFO rules).

FIA

Fixed Indexed Annuity

An accumulation product where interest credits are tied to a market index (S&P 500, Russell 2000, etc.), with a guaranteed floor (no market loss). Often paired with a guaranteed lifetime withdrawal benefit rider. Complex; pricing varies widely.

Tax: deferred during accumulation; withdrawals ordinary income.

Variable Annuity

Premium invested in sub-accounts (essentially mutual funds inside an insurance wrapper). Account value rises and falls with market performance; principal can be lost. Often layered with optional living-benefit riders. The most expensive annuity type by fee structure.

Tax: deferred during accumulation; gains taxed as ordinary income on withdrawal.

A deeper page on the tax mechanics — exclusion ratio details, the LIFO ordering rules on non-qualified annuity withdrawals, qualified vs non-qualified treatment, 1035 exchanges, RMDs on annuitized accounts — is on the roadmap. This page sticks to the SIS-vs-SPIA distinction and the §453 gross-profit-ratio math.

An SIS uses an annuity. It is not a SPIA.