Update: JCT Tax Expenditures $2.3T→$2.42T, OASDI Clock 2034→2033, GSE MBS +$0.3T

What changed since the research map

Our fiscal plumbing research map answered the theme’s core question — which budget lines, trust funds, and off-balance vehicles move real levers? — with three anchors: JCT tax expenditures at about $2.3T in FY2026, combined OASDI reserves depleting around 2034, and Fannie/Freddie MBS steering roughly $7.8T of housing credit off-budget. That post was the system diagram. This update is the vintage delta: what moved once the newest official prints landed?

Three information events rewrite the scoreboard. JCT’s FY2027 tax-expenditure path, as summarized in the summer-2026 CRFB refresh, lifts the aggregate from $2.3T to about $2.42T (+$0.12T, +5.2%). The 2026 SSA and Medicare Trustees Reports pull the exhaustion clocks forward one year: OASDI 2034 → 2033, HI 2036 → 2035. And mid-2026 FHFA stock figures put guaranteed GSE MBS near $8.1T, up +$0.3T from the research round. Net interest — the quiet first claim on revenue — also steps up in the CBO outlook framing we carry here: ~$970B → ~$1.05T.

The dashboard above is built as a research→newest vintage delta: diverging change bars, JCT top-line prior/new composites, dual-vintage trust reserve paths, depletion-year dumbbells, plumbing-layer bars, an off-balance leverage scatter, and the Treasury-vs-JCT ESI packaging gap. Use the layer filter and JCT family controls to isolate tax-code, trust-fund, off-balance, or interest moves.

The headline table: research map → newest official vintage

The story is not “discretionary suddenly matters.” Discretionary barely budges. The levers that moved are the ones the research map already flagged as high-leverage and low-visibility: the tax-code shadow budget, the trust-fund clocks, and the housing-credit guarantee book.

Tax expenditures: the shadow budget grew another $120B

Toggle Layer filter → Tax code. The JCT aggregate is the cleanest public meter of “spending through the Code.” Moving from the FY2026 research print ($2.3T) to the FY2027 path (~$2.42T) adds roughly $120B of annual shadow budget — more than the entire discretionary delta in the table above. The top-ten lines alone add about $84B, led by pensions/retirement (+$23B), preferential capital-gains and dividend rates (+$16B), and the employer-sponsored health exclusion (+$15B).

Two caveats travel with every tax-expenditure chart. Do not sum line items as the revenue from simultaneous repeal — interactions and behavior matter. And refundable credits blur revenue loss and outlays; the deficit impact is real either way. For the line-item ranking deep dive, pair this update with our tax-expenditure catalog. For industrial-policy credits that live on the same Code, see the fiscal and industrial policy series.

Filter JCT family → health and the ESI line is the packaging story, not just the level story. Treasury’s published employer-medical headline still sits well above JCT’s ESI concept. The packaging gap narrows only slightly — $56B → $52B — which means analysts who cite only one office can still cherry-pick a preferred giant. Methodology, not a spreadsheet error.

Trust funds: the entitlement spine pulled forward one year

The research map used mid-2020s Trustees framing: OASI ~2033, OASDI combined ~2034, Medicare HI ~2036, with SMI remaining premium-and-general-revenue financed rather than a classic exhaustion clock. The 2026 Trustees Reports do not invent a new crisis architecture. They move the clocks. Combined OASDI now prints ~2033; HI prints ~2035. OASI itself shifts 2033 → 2032 in the rounded path we carry. DI remains long-solvent on a multi-decade horizon; SMI still has no depletion year in the classic sense.

That one-year pull-forward matters for politics more than for actuarial novelty. Markets already price the idea that payroll-tax and benefit-formula fights arrive before the 2030s are over. A 2033 combined date compresses the legislative runway by a session. Pair the dual-vintage reserve path in the dashboard with our Social Security depletion path for the household-level framing; this update is the Trustees restatement of the system clock those posts sit inside.

Reserve stocks move with the clocks. We carry combined OASDI reserves from roughly $2.7T → $2.55T and HI from ~$0.23T → ~$0.20T in the estimated path — rounded, labeled, and not a live scoreboard tick. The dumbbell panel makes the year deltas the object: every exhausting fund we track moves earlier or stays flat; none move later.

Off-balance credit: GSE MBS is still the quiet housing lever

Filter Layer filter → Off-balance. The research map’s punchline still holds: the guarantee books that steer mortgage rates, underwriting standards, and deposit risk rarely show up as appropriation-title fights. What changed is scale. GSE guaranteed MBS rises from about $7.8T to $8.1T. Federal Direct Student Loans tick $1.6T → $1.65T. FDIC-insured deposit stock and FHA/VA exposure edge higher in the rounded mid-2026 prints; PBGC risk stock is roughly flat.

The scatter panel puts the same vehicles on two axes the unified deficit does not: budget visibility versus policy leverage, with bubble size proportional to newest stock. GSE MBS remains the extreme: enormous stock, low appropriation visibility, very high leverage over housing credit. Student loans sit higher on visibility because credit-reform scoring and forgiveness debates force them onto the partisan stage — which is why they look anomalous next to the quiet GSE book. Deposit insurance is the systemic backstop: low day-to-day budget noise, near-maximal leverage when it matters.

Read the off-balance deltas as stock, not flow. A +$0.3T GSE move is not a $300B appropriation. It is additional guaranteed credit that steers who gets a mortgage and at what rate while the discretionary fight argues over tens of billions.

Net interest vs discretionary: the loud fight is still the small delta

Net interest in the outlook framing we carry steps from about $970B to $1.05T (+$80B). All discretionary moves roughly $1.70T → $1.72T (+$20B). That ratio is the political irony of fiscal plumbing: the line Congress argues about loudest grows least, while the first claim on revenue and the permanent-law Code grow without an annual floor amendment. Interest is not a “program” anyone votes to expand; it is the arithmetic of the debt stock rolling at higher coupons.

The plumbing-layer bars make the composition point without pretending to be a single official CBO pie. Tax expenditures and SS/Medicare outlays remain the two largest annual-flow layers on our editorial map; discretionary is third; net interest is closing. Medicaid and other health mandatory also step up. None of these layers sum to “the budget” without double-counting and definition fights — which is why the research post warned against treating the pie as an accounting identity. The update inherits that caveat and asks only what moved.

What did not change — and why that matters

Several research-map conclusions survive the vintage. SMI is still not an exhaustion clock in the OASI/HI sense. DI remains long-dated relative to OASI. Tax expenditures still dwarf any single discretionary title on a like-for-like annual scale. Off-balance credit still steers housing and education without looking like spending in the cable-news sense. The ESI packaging gap between Treasury and JCT narrows slightly but does not close.

What changed is timing and magnitude at the margin that markets and legislative calendars actually feel: a larger Code, an earlier OASDI/HI date, a bigger GSE book, and a higher interest bill. Those are the real levers. The appropriation titles remain the theater.

How to read the dashboard

Start with All layers on the diverging delta bars to see which meters moved in which direction. Year shifts are scaled for visibility; hover for the true year delta. Switch to Tax code and then use JCT family to isolate retirement, capital, or health lines. Open the dual-vintage trust path to compare dashed prior reserves against solid newest paths, then the dumbbell for the depletion-year restatement. Finish on the off-balance scatter and ESI gap panel if the question is packaging and guarantee leverage rather than outlay headlines.

Caveats and source boundaries

Trust-fund depletion years and reserve paths are rounded from Trustees framing — not a live actuarial score. Off-balance figures are outstanding or exposure stocks for scale, not annual outlays. Tax-expenditure line items interact; do not treat the top-ten sum as a joint-repeal score. Layer composition bars are an editorial map for orientation, not a substitute for the unified budget. Where we mark confidence as estimated, the direction of the vintage delta is the claim, not the last significant digit. Primary anchors: CRFB summaries of JCT FY2026 and FY2027-path prints, 2026 SSA and Medicare Trustees Reports, FHFA GSE MBS outstanding, Education Direct Loan portfolio, and CBO net-interest outlook framing.

Unlike the research map alone, this piece is the delta tape: what the newest official vintage moved on the same three plumbing layers. Unlike a single trust-fund or tax-catalog post, it keeps the system diagram intact so a one-year OASDI shift and a $0.3T GSE move stay comparable on one screen.