CHIP runs on a capped budget. That's what makes its flat line strange.

Medicaid is an open-ended entitlement: whatever a state spends on eligible people, the federal government matches, with no ceiling.▸ CHIP, its smaller sibling for children just above the Medicaid income line, is the opposite — a capped block of federal money, set once a year, that runs out if a state overspends it. On paper that should make CHIP the more fragile program. Over the last twelve months it hasn't worked out that way: CHIP enrollment barely moved while Medicaid enrollment fell hard.

CHIP is a joint federal-state program, but the federal government pays the larger share.▸ In fiscal year 2023, states and territories spent $23.4 billion combined on CHIP-funded coverage — $17.4 billion of it federal money, per MACPAC's MACStats Data Book, which tracks state-by-state CHIP spending using CMS's own expenditure records. Most of that money — $15.3 billion — pays for children whose coverage counts as "Medicaid-expansion CHIP": states use CHIP dollars to cover kids inside their Medicaid programs. Another $7.1 billion runs states' free-standing separate CHIP programs, plus coverage for pregnant women in seven states that use CHIP funds that way. Just over $1 billion — about 4 cents of every CHIP dollar — pays for running the program itself: eligibility systems, outreach, staff.

The federal share isn't a flat match rate — it's an "enhanced" version of each state's regular Medicaid match, calculated under a formula in Section 2105(b) of the Social Security Act: take a state's regular Medicaid match rate, close 30% of the remaining gap to 100%, and cap the result at 85%.▸ For fiscal year 2026, that formula sends wealthier states — California, New York, Massachusetts, and seven others — to the statutory floor of 65%, while Mississippi's lower per capita income pushes its rate to 83.83%, the highest of any state. The four U.S. territories with a CHIP program are set by statute at the maximum, 85%.

That enhanced match rate is generous, but it only applies to a fixed pot.▸ Each year, per CRS's overview of CHIP financing, every state gets a capped federal allotment — sized off its recent CHIP spending and adjusted for health-cost and child-population growth. If a state's CHIP costs run ahead of its allotment, it can draw on a national Child Enrollment Contingency Fund or on money redistributed from states that under-spent their own allotments in the prior two years. If those sources still don't cover it, the state is on its own. Medicaid has no equivalent ceiling; CHIP has always had one. The Consolidated Appropriations Act, 2023 extended CHIP's federal allotments, its redistribution and contingency-fund mechanisms, and a "maintenance of effort" rule barring states from tightening children's eligibility below current levels — all through fiscal year 2029. The money and the eligibility floor are both locked in for another three years.

None of that financing structure explains why CHIP enrollment has held up better than Medicaid's over the past year — the two programs' caseloads move for administrative and behavioral reasons, not funding-formula ones.▸ But the contrast is real and it's recent. Between February 2025 and February 2026, per CMS's monthly Medicaid and CHIP enrollment snapshot, CHIP enrollment slipped from 7.4 million to 7.2 million — down 130,000 people, or 2%. Medicaid, over the same twelve months, fell from 71.3 million to 67.7 million — down 3.7 million people, or 5%.

Nobody changed the income rules that decide who qualifies for either program during this period — both are still means-tested at the same thresholds they were a year ago, as the Georgetown Center for Children and Families has documented.▸ What's moved instead is who successfully makes it through a renewal or stays enrolled through paperwork churn — and, researchers suspect, a "chilling effect" among mixed-status immigrant families wary of enrolling citizen children in any public program. The larger cuts to Medicaid eligibility rules passed in 2025's reconciliation law haven't fully phased in yet; CHIP's steadier line so far measures the period before that law starts to bite, not immunity from it.

The 8.9 million figure counts children only (MACPAC's Exhibit 32, child enrollment in Medicaid-expansion CHIP plus separate CHIP); the $7.1 billion separate-CHIP spending figure in the money-flow chart also includes coverage for pregnant women in seven states, so the two totals aren't directly comparable population counts. The February 2025–2026 enrollment comparison uses CMS's monthly Performance Indicator Data, a different and broader snapshot definition that includes pregnant women; CMS advises against comparing figures across its own data sets, so the FY2023 exhibits and the monthly snapshot are presented here separately rather than combined into one series.