No health insurer publishes its provision for adverse deviation. Every one of them publishes the next best thing: a roll-forward of claims payable showing how much of last year's reserve turned out to be unneeded. Divide that release by the opening reserve and a carrier that lets go of about the same share every year is showing you its margin. In the latest filings the share runs from 3.2% at UnitedHealth to 13.6% at Oscar (Forms 10-Q and 8-K, July to October 2026).
The spread between carriers says little, because their reserves turn at different speeds. The change within one carrier says a lot. Measured against each company's own 2022 to 2025 average, four of the seven are releasing less than their run rate this year. Two are releasing more, and one is within a point. Molina posted a 2.1% release for 2025 against a 12.2% average in the three years before. It is the clearest case in the group of a margin eroded by claims that ran above the pick.
Key Takeaways
- Molina's 2025 release collapsed to 2.1% of its opening reserve from a 12.2% post-COVID average; 2026 is rebuilding at 7.2%.
- Aetna went the other way: 13.2% for 2025 against a 7.4% average, then back to 8.1% in the first half of 2026.
- Centene and Humana are running below their run rates at 8.7% and 4.4%, but both added three to four points in last year's second half.
- UnitedHealth releases the least and is above its own rate: 3.2% against a 1.8% average, on a favorable respiratory season.
- Oscar has released about 18% two years running after three adverse years, and sits at 13.6% through June.
- Risk adjustment is a second prior-year line for marketplace carriers. Oscar's went $68M adverse in 2025 while its claims line released 18.5%; Centene's 2025 benefit year settled $541M favorable in June.
The Release Ratio as a Proxy for the Margin
The table behind this piece is the short-duration claims disclosure every insurer carries in its 10-K and repeats each quarter. The incurred line splits into current-year claims and the change in estimate for prior years. A negative prior-year figure means last year's reserve was more than the claims that arrived against it. Dividing that figure by the net opening payable gives the share of the starting reserve that proved unneeded.
Carriers describe that share as a design feature. Molina writes that its reserve carries a provision for moderately adverse conditions. The provision "is recognized as favorable prior period development but is replenished at similar levels in the current IBNP estimates" (Molina 10-K, February 2026). Centene attributes its development to "reserving under moderately adverse conditions." A carrier that releases 12% of its reserve every year is therefore telling you the size of the margin it books. The proxy is the magnitude of the favorable year.
The reading runs in both directions. A year far below the run rate means the margin was spent. Claims against last year's reserve came in above the best estimate, through utilization, unit-cost inflation or a trend assumption set too low. The provision absorbed the difference instead of releasing it.
The reserve still held, which is what the provision is for. But the cushion that normally shows up as favorable development was consumed. Days in claims payable is the companion check: the reserve divided by one day of claims expense. A release that shrinks while days rise points to a reserve being rebuilt, or to slower claims; a release that shrinks while days fall points to a reserve being spent. A year far above the rate means the opposite: the pick was set too high, often after a bad year, and the excess came back.
Two conventions make the comparison usable. COVID years are left out of the baseline. Reserves set at the end of 2020 under lockdown uncertainty ran off in 2021. That was the largest release year of the decade at Centene and UnitedHealth and the second largest at Elevance, and 2020 itself was distorted by suspended care. The baseline here is the four full years 2022 to 2025.
The comparison is within one carrier, never across carriers. UnitedHealth paid $32,474 million of prior-year claims in six months against an opening payable of $39,337 million (UnitedHealth 10-Q, June 2026). A 3% release on a reserve that short is a different quantity from 13% on a book that still carries disputed claims months later.
The 2026 figures are year to date. Health claims settle fast, so a nine-month ratio is close to the full year, and Elevance's and Molina's nine-month 2025 ratios landed within a point of their full-year figures. Six-month ratios are less complete. Centene's rose 3.1 points between June and December last year, Humana's 3.8 points and Oscar's 5.9. A six-month 2026 figure below the average is partly a matter of when the release gets booked. Five of the seven carriers report their third quarter between now and early November, and this table will be updated as they do.
Seven Carriers Against Their Own Run Rate
| Carrier | 2026 YTD | 2025 YTD | FY 2025 | FY 2024 | FY 2023 | FY 2022 | Avg 2022-25 | 2026 vs avg |
|---|---|---|---|---|---|---|---|---|
| Oscar | 13.6% (6M) | 12.6% | 18.5% | 18.1% | (3.0%) | (0.4%) | 8.3% | +5.3 pts |
| Centene | 8.7% (6M) | 9.6% | 12.7% | 13.6% | 12.2% | 9.6% | 12.0% | -3.3 pts |
| CVS/Aetna | 8.1% (6M) | 12.7% | 13.2% | 7.8% | 6.8% | 7.5% | 8.8% | -0.7 pts |
| Elevance | 7.7% (9M) | 8.1% | 8.3% | 10.9% | 10.2% | 6.6% | 9.0% | -1.3 pts |
| Molina | 7.2% (9M) | 2.7% | 2.1% | 16.1% | 12.1% | 8.4% | 9.7% | -2.5 pts |
| Humana | 4.4% (6M) | 6.1% | 9.9% | 6.8% | 9.4% | 5.0% | 7.8% | -3.4 pts |
| UnitedHealth | 3.2% (6M) | 0.9% | 0.4% | 2.2% | 2.9% | 1.7% | 1.8% | +1.4 pts |
Ratio: favorable prior-year development divided by the net claims payable at the start of the period. Full years come from each carrier's 10-K roll-forward; 2026 and 2025 year-to-date figures come from its latest 10-Q or earnings release. Parentheses mark adverse development. CVS/Aetna's 2022 uses the opening balance as restated for the long-duration insurance standard. Oscar's figures are the benefits payable column of its table, excluding unallocated claims adjustment expense and risk adjustment. Every roll-forward was footed from opening balance through incurred and paid to closing balance.
Days in claims payable adds the second axis. Six of the seven carriers publish it, each on its own definition (Humana's is consolidated and includes fast-paying pharmacy claims; Aetna's is the Health Care Benefits segment on quarterly expense; Molina's uses fee-for-service costs only). The computed column puts all seven on one basis: ending net payable divided by average daily incurred claims over the period, which runs a few days above a quarterly-expense figure in a growing book and is not comparable to the published numbers, only across carriers and years.
| Carrier | Published, latest | Published, year ago | Published, Dec 2025 | Computed, latest | Computed, year ago | Computed FY 2025 | Computed FY 2024 |
|---|---|---|---|---|---|---|---|
| Elevance | 44.9 (Sep 30) | 41.4 | 41.3 | 45.9 | 42.9 | 42.5 | 46.1 |
| Molina | 44 (Sep 30) | 46 | 47 | 47.9 | 45.1 | 45.2 | 49.3 |
| UnitedHealth | 47.0 (Sep 30) | 46.2 | 44.1 | 47.3 | 45.8 | 45.7 | 47.4 |
| CVS/Aetna | 41.7 (Jun 30) | 40.9 | 38.9 | 48.3 | 43.5 | 44.7 | 47.8 |
| Centene | 47 (Jun 30) | 47 | 46 | 47.3 | 48.4 | 47.3 | 53.0 |
| Humana | 33.1 (Jun 30) | 36.5 | 31.9 | 33.7 | 37.0 | 32.8 | 38.0 |
| Oscar | not published | 47.3 | 57.6 | 52.1 | 64.8 |
Published figures are from each carrier's earnings release for the period shown; the year-ago column is the same quarter of 2025. Computed figures use the roll-forward tables cited above: 273 days for nine-month periods, 181 for six-month periods, and the calendar year for full years. Oscar's computed days fell from 65 to 47 over two years as its quota share ran off and its paid claims caught up with incurred.
Molina is the eroded margin, and the carrier that explains it in the most detail. Its releases ran 8.4%, 12.1% and 16.1% in the three post-COVID years, then 2.1% in 2025. That was $98 million on a $4,640 million opening balance, with the Marketplace segment adverse by $61 million (Molina 10-K, February 2026).
On the fourth-quarter call Joseph Zubretsky described the year that spent the margin: "medical cost trend continually increased from 4.5% in initial guidance to 7.5%, an unprecedented inflection in such a short period of time. 250 basis points of this 7.5% trend is attributable to the acuity shift from membership declines" (Molina Q4 2025 call, February 2026). His CFO, Mark Keim, put it more briefly: "rates have not kept up with trend over the past 6 quarters."
The 2026 rebuild is $352 million through nine months, 7.2% of the opening balance and 2.8 times last year's pace, split $203 million Medicaid, $114 million Medicare and $28 million Marketplace (Molina 10-Q, October 2026). Keim told analysts this week that reading it as a bigger contributor is "somewhat misguided.
Compared to last year, that's true, but as you know, last year, prior year development was significantly lower than it normally would be" (Molina Q3 2026 call, October 2026). Full-year trend guidance moved to 5.5% from 5%, half core trend and half an acuity re-estimate. On the proxy, 2026 is a return toward the old run rate that is still 2.5 points short of it, with days in claims payable at 44 against 47 at year end.
CVS/Aetna is the mirror image, and its 10-K itemizes the mechanism. The ratio sat between 6.8% and 7.8% from 2022 to 2024, then jumped to 13.2% in 2025 on $1,982 million of development. Claims with fourth-quarter 2024 dates of service came in 6.1% below the year-end estimate, worth $1.4 billion, against 3.2% and $546 million a year earlier, and completion factors ran 31 basis points above assumption, worth $541 million (CVS Health 10-K, February 2026).
The same filing says the segment had loaded its trend assumption for the most recent three months 3.4% above observed trend when it set the 2024 reserve, in a year it also booked premium deficiency reserves of $766 million on Medicare and $270 million on the exchange. The pick was set high after a bad year, and 2025 came in under it. The first half of 2026 is back at 8.1%, within a point of the old rate, and the year-end 2025 reserve carried a 4.4% trend load.
Centene is the steadiest book in the group at 12.2%, 13.6% and 12.7% for the three full years. On this reading that is a margin of about one eighth of the reserve, booked and released every year. Its six-month 2026 figure of 8.7% is 3.3 points under the average. But 2025's six-month figure was 9.6% and the full year ended at 12.7%, so the gap at this point last year was similar (Centene 10-Q, July 2026).
Medicaid supplied $1,000 million of the $1,778 million. Nothing in management's commentary points the other way: CFO Drew Asher raised the full-year rate impact to about 5% "with no change in our view of fundamental trend of mid-four for the year," naming behavioral health, home health and high-cost drugs as the persistent drivers (Centene Q2 2026 call, July 2026). Days in claims payable were 47, flat on a year ago. Third-quarter results come October 27.
Elevance has drifted down for two years: 10.9% in 2024, 8.3% in 2025 and 7.7% for nine months of 2026, 1.3 points under its average. Its third-quarter 10-Q, filed this week, splits the $1,295 million release half and half: $652 million from completion factors against $231 million a year ago, and $643 million from trend factors against $1,035 million (Elevance 10-Q, October 2026).
The same filing says claims payment speed was "slightly slower" than a year ago, with current-year claims paid at 85.1% of incurred against 86.3%, and days in claims payable at 44.9, up 3.5 days. In January the CFO, Mark Kaye, had guided days to "remain in the low 40s range consistent with our long-term target."
That is the slower-claims reading rather than the eroded-margin one. Claims arrived later than assumed, the completion factors released more and the trend factors less, and the reserve grew relative to claims. Elevance's own development ratio, which nets the redundancy out of the denominator, reads 8.4% against 8.9%, and the filing calls the level of conservatism "appropriate and consistent." Trend is the other half of the story: Kaye described Medicaid cost trend as "elevated and broadly stable" with rates that "have certainly not fully caught up with the underlying costs" (Elevance Q3 2026 call, October 2026). The release line is not where that pressure shows; the benefit ratio is.
Humana runs below its average at 4.4% for six months against 7.8%, and by its own account that was the plan. Every 2026 filing lists "the anticipated lower favorable prior-period medical claims reserve development in 2026" among the reasons the benefit ratio rose (Humana 10-Q, July 2026). The 2025 full year of 9.9% was the highest of its post-COVID years, with $541 million from trend factors and $488 million from completion factors, and the second half added 3.8 points last year.
CFO Celeste Mellet said trend is running inside the 7% to 8% assumption with inpatient favorability, "both the P and the Q on inpatient costs that are down," and that IBNR "remained basically flat from last quarter. We view this as still very prudent" (Humana Q2 2026 call, July 2026). Days in claims payable fell to 33.1 from 36.5, which the release attributes to lower claims inventories, capitation timing and a growing pharmacy mix that settles faster. Humana's 2025 10-K also dropped the phrase "moderately adverse conditions" that earlier filings used to describe the reserve basis.
UnitedHealth releases the least of any carrier in any year, between 0.4% and 2.9% since 2022. It is now above its own rate at 3.2%, on $1,250 million it credits to "a favorable respiratory illness season." The six-month figure also carries a $236 million release of premium deficiency and loss contract reserves after a $672 million charge in 2025. Days claims payable were 47.0 at September 30 against 46.2 a year ago, after dipping to 44.1 at year end on the Inflation Reduction Act's Part D changes (UnitedHealth 8-K, October 2026).
The release's own $610 million of "net favorable prior period reserve development" is a different quantity: it relates to 2026 dates of service, in-year development that never touches the prior-years line. On trend, UnitedHealthcare's Tim Noel said in July that Medicare costs were "still running well above historical levels but below our expectations," while commercial trend was running above 11%.
Oscar is the one carrier whose post-COVID average is not a run rate. Its 2022 and 2023 were adverse. Then 2024 and 2025 released 18.1% and 18.5% as its quota share ran off and its net reserve nearly tripled (Oscar 10-Q, August 2026).
Its 13.6% through June compares with 12.6% at the same point last year. Oscar does not publish days in claims payable; on the computed basis its reserve covers 47 days of claims against 58 a year ago. Its call figure needs the same care as UnitedHealth's: the $164 million of "favorable prior period development" management cited for the second quarter is mostly a 2025 risk-adjustment true-up ($144 million on Oscar's risk adjustment roll-forward, below), which the claims roll-forward excludes.
Taken together, four of the seven are below their post-COVID rate through the latest filing, and management's explanations sort them. Humana's gap is guided. Centene's was the same size at this point last year and closed by December. Elevance's is completion factors and slower claims, with the reserve growing. Molina's is the one that reads as a margin spent, and it was spent in 2025; 2026 is the rebuild. The erosion reading, in other words, fits one carrier and one year so far.
Where the Release Goes Before It Reaches Earnings
Four carriers say in the same note that the release and the earnings benefit are different numbers. Centene recorded $38 million of its six-month development as a reduction to premium revenue under minimum MLR and return-of-premium programs. The same give-back was $93 million, $243 million and $382 million for 2025, 2024 and 2023 (Centene 10-K, February 2026). A Medicaid contract that caps the carrier's margin returns part of any reserve release to the state. The ratio counts the gross figure.
Humana's 10-Q says the development "does not directly correspond to our operating results," because a portion sits in provider risk-sharing arrangements accounted for separately. Aetna's 10-K says its prior-year development was offset by the current-period estimate. Molina's says 2025's development "was partially absorbed by minimum MLRs and medical cost corridors." These offsets do not change the proxy, since the reserve was set gross of them. They do mean a 12% release is not 12% of the reserve dropping to the bottom line.
| Carrier | Item outside the prior-year line | Latest figure | Year-ago figure |
|---|---|---|---|
| Centene | Minimum MLR and return-of-premium give-back | $38M (6M 2026) | $69M (6M 2025) |
| Centene | Premium deficiency reserve, Medicare Advantage | none for 2026 | $297M added (6M 2025) |
| CVS/Aetna | Premium deficiency reserves | $15M | $902M |
| UnitedHealth | Premium deficiency and loss contract reserves | $236M release (6M 2026) | $672M charge (FY 2025) |
| Humana | Provider risk-sharing arrangements | not quantified | not quantified |
| Molina | Minimum MLR and medical cost corridors | not quantified | "partially absorbed" (FY 2025) |
Premium deficiency reserves are the complication that sits closest to the proxy. A PDR is booked when expected claims on a contract year exceed the premium, and it sits outside the incurred line in every one of these tables. Aetna's $902 million at June 2025 was down to $15 million a year later. UnitedHealth charged $672 million in 2025 and released $236 million of it in the first half of 2026. Centene added $297 million for its 2025 Medicare Advantage year and has recorded nothing for 2026.
The release ratio and the deficiency reserve measure the same book from different directions. Aetna's 13.2% release for 2025 came out of a reserve set at the end of 2024. That year it also carried more than a billion dollars of deficiency reserves on contracts that were losing money. A margin read from the release line alone was too high for 2024 and looks ordinary for 2025, while the deficiency line went the other way.
Risk Adjustment Carries a Second Prior-Year Line
The claims roll-forward is one of two places a prior year gets re-estimated. Marketplace carriers also accrue an ACA risk adjustment transfer on each benefit year from estimated relative risk scores. CMS publishes the final transfers the following June, so the June quarter carries a true-up of last year's accrual. That true-up is prior-year development too. It runs through premium revenue rather than benefit expense, and it sits outside every table above. Three of the seven carriers quantify it, and only Oscar presents it as a roll-forward.
Oscar added the roll-forward to its second-quarter 2025 10-Q and has carried it in every filing since. The table reads like the claims table: an opening net payable, the current-year accrual, the change in the accrual for prior years, and the closing balance. Centene gives a point-in-time balance table for the ACA programs and one sentence a year on the CMS announcement. Molina states its gross payable, receivable and net position in prose and gives no true-up figure. Elevance, Aetna, UnitedHealth and Humana disclose no ACA risk adjustment amounts; Aetna left the exchanges in January 2026 and Humana has no marketplace book.
| Carrier | Disclosure | Net position, latest | Net position, Dec 31, 2025 | Prior-year true-up, 2026 YTD | FY 2025 | FY 2024 |
|---|---|---|---|---|---|---|
| Oscar | Roll-forward, since Q2 2025 | $4,846M payable (Jun 30) | $2,532M payable | $59M favorable (6M): Q1 $85M adverse, Q2 $144M favorable | $68M adverse | $23M adverse |
| Centene | Balance table plus one CMS final-transfer sentence a year | $186M payable (Jun 30) | $638M payable | $541M favorable (2025 benefit year); $481M pre-tax after offsets | $504M adverse (2024 benefit year); $163M pre-tax after offsets | $1,475M favorable (2023 benefit year); $853M pre-tax after offsets |
| Molina | Balances in prose, no true-up figure | $78M payable (Sep 30) | $411M payable | favorable, not quantified | not quantified | not quantified |
| Elevance, CVS/Aetna, UnitedHealth, Humana | No ACA risk adjustment amounts disclosed | n/a | n/a | n/a | n/a | n/a |
True-up: the change in the net risk adjustment position for prior benefit years during the period; favorable means the net payable fell or the net receivable rose. Oscar's figures are its roll-forward's prior-years line, in thousands in the filing and rounded here. Centene's are the CMS final-transfer sentence in each 10-K and 10-Q, with the pre-tax effect after minimum MLR, RADV and other offsets. Molina's net payable was $565 million at June 30, 2026 and $98 million at December 31, 2024; Centene's was $171 million at December 31, 2024.
Oscar's two lines moved against each other through 2025. Its claims reserve released 18.5% of the opening payable, the largest ratio in the group, while the risk adjustment accrual for prior years went adverse by $68 million, 4.6% of the opening net payable. The 10-K explains the adverse year: third-party reports in the second and third quarters showed market risk scores "significantly higher than the overall market expectation", and fourth-quarter reports showed Oscar's own relative scores "lower-than-anticipated". A margin read from the claims line alone overstated 2025. The two lines together are the proxy for a marketplace carrier.
The first half of 2026 reversed the sign. The prior-years accrual change was $85 million adverse in the first quarter and $144 million favorable in the second, $59 million favorable net. That second-quarter figure is the risk adjustment part of the $164 million of prior-period development management cited on the call, and it is why the call figure and the claims roll-forward's $194 million do not match. The net risk adjustment payable has nearly doubled since December, to $4.85 billion, on higher membership and a higher payable per member.
Centene's true-ups are of the same order as its claims line. The 2023 benefit year settled $1,475 million favorable in July 2024, an $853 million pre-tax benefit after minimum MLR and other offsets, against a $2,447 million claims release that year. The 2024 benefit year went the other way in July 2025: the net receivable fell $504 million, and the year's net benefit was $163 million after offsets.
The 2025 benefit year came in $541 million favorable this June, almost all of the $545 million net payable Centene held for that year at December 31, for a $481 million pre-tax benefit. An accrual that the final transfer nearly erases was conservative by about the size of the accrual.
Molina's balances say what its MD&A sentence does not quantify. The net payable fell from $565 million at June 30 to $78 million at September 30, and the third-quarter marketplace MCR improved 310 basis points "mainly due to the impact of favorable changes in estimate for risk adjustment premiums." The nine-month MCR moved the other way, on "changes in estimate for prior year risk adjustment premiums." Marketplace membership fell 446,000 over the year to 267,000, so the smaller payable is partly a smaller book.
The proxy works carrier by carrier and year by year; it does not work on one line of one table in one quarter. Five of the seven figures above are six months old. The first test of the reading is whether the third-quarter 10-Qs move Centene and Humana back toward their rates the way last year's second half did, and whether Oscar's risk adjustment line keeps its new sign.
Further Reading
- Elevance Lifts Guidance as Its Insurance Margin Falls to 1.0%: the third-quarter reserve build behind Elevance's 7.7%.
- Aetna's 250bp MBR Drop Rode a $471M Reserve Reversal: the premium deficiency reserve that reversed inside Aetna's second quarter.
- Molina's 92.7% Medicaid MLR and a Trough Call the Acuity Math Hasn't Confirmed: the second-quarter trough call that the reserve table now sits under.
- UnitedHealth and Elevance Split the Q2 2026 Managed-Care Recovery: the two largest carriers' ratios a quarter earlier.
- Centene's Marketplace Book Shrank 41 Percent. Its Risk-Adjustment Position Swung Favorable With It: the marketplace book behind Centene's late-arriving claims.
Sources
- Elevance Health, Form 8-K Exhibit 99.1, third quarter 2026, October 21, 2026; Forms 10-K 2022 to 2025, Note 12
- UnitedHealth Group, Form 10-Q for June 30, 2026, Note 4; Forms 10-K 2022 to 2025, Note 7
- CVS Health, Form 10-K 2025, Note 7, and Form 10-Q for June 30, 2026
- Centene, Form 10-K 2025, Note 8, and Form 10-Q for June 30, 2026, Note 6
- Humana, Form 10-K 2025, Note 11, and Form 10-Q for June 30, 2026, Note 8
- Molina Healthcare, Form 10-K 2025, Note 10, and Form 8-K Exhibit 99.1, third quarter 2026, October 21, 2026
- Oscar Health, Form 10-K 2025, Note 8, and Form 10-Q for June 30, 2026, Note 7
- Elevance Health, Form 10-Q for September 30, 2026, Note 8 and MD&A (filed October 21, 2026)
- Molina Healthcare, Form 10-Q for September 30, 2026 (filed October 22, 2026)
- Oscar Health, Form 10-Q for June 30, 2026, Note 8 (risk adjustment roll-forward), and Form 10-Q for March 31, 2026, Note 8
- Centene, Form 10-Q for June 30, 2026, Note 7 (Affordable Care Act), and Form 10-K 2024, Note 9
- Earnings call transcripts: Molina Q4 2025 (Motley Fool) and Q3 2026 (MarketBeat); Elevance Q3 2026 (Motley Fool); Centene Q2 2026 (MarketBeat); Humana Q2 2026 (Webull); CVS Health Q4 2025 (FactSet transcript on the CVS investor site). Quotes checked against the transcript text; third-party transcriptions may differ slightly from the audio.