A large new brain study estimating that at least one in four former NFL players developed a degenerative brain disease is landing in the middle of a billion-dollar insurance fight - and adding urgency to how underwriters price concussion risk across contact sports.
Researchers from Mass General Brigham, Boston University, and the Concussion & CTE Foundation reported in The BMJ that of 878 former NFL players who died between 2016 and 2021, 235 families donated the player's brain for examination, and 215 of those brains showed evidence of chronic traumatic encephalopathy (CTE). That works out to a minimum prevalence of 24.5% across the full group of players who died in that period - a figure the study's authors describe as conservative, since it treats every undonated brain as CTE-free.
Applied to today's league - roughly 1,696 players on 32 regular-season rosters, before counting practice squads - the rate implies at least 400 current players could eventually be diagnosed with the disease. That's a striking exposure figure for a business that generated more than $23 billion in revenue in its most recent fiscal year.
CTE, first identified in boxers nearly a century ago, is a progressive condition linked to repeated head impacts. It cannot be confirmed in a living person; diagnosis requires examining brain tissue after death. Symptoms researchers associate with the disease include memory loss, impaired judgement, mood disturbance, and dementia in its more advanced stages.
The study lands just as the NFL's decade-long dispute with its own liability insurers is finally headed for trial. Litigation over who bears the cost of the league's concussion settlement fund - which has paid out well over $1 billion to retired players and is still growing - is scheduled to go before a New York court on October 13, 2026, with more than $1.5 billion in disputed payouts on the line. At the dispute's peak, roughly 30 insurers were drawn in; the NFL has settled with a number of them over the years, though it's unclear from public reporting exactly how many carriers remain as holdouts heading into the October trial. Those that remain have argued in court filings that the league knew about, and allegedly downplayed, the risks of head trauma before its policies were underwritten - a fact pattern that, if proven, could trigger exclusions tied to known or expected loss.
A prevalence rate this high strengthens the players' side of that underlying argument and narrows the room insurers have to dispute causation. It also gives class counsel and plaintiffs' experts a peer-reviewed, population-level benchmark to point to, rather than relying solely on the self-selected sample of brains donated because a family already suspected something was wrong.
Insurance Business has tracked this fight for close to a decade, from the years when insurers first began settling with the league through the period when carriers pushed back on the size of the payout altogether. What has changed is the denominator: this study is the first to model prevalence across a whole population of deceased players rather than just the donor pool, which is exactly the kind of actuarial-grade data that tends to move settlement negotiations and reserving decisions.
The prevalence question isn't confined to American football, or to the professional level. The broader sports insurance market - now estimated at roughly $2 billion in premium and covering everything from youth leagues to major venues - has already been recalibrating around head-injury exposure for several years. Speaking to Insurance Business, Amwins-affiliated underwriter SMIC described three distinct strategies that carriers take toward traumatic brain injury exposure: decline the risk outright, quote with a sublimit or exclusion attached, or price in full and accept the volatility.
Overseas, some insurers are moving toward the first two options. In Australia, Zurich confirmed earlier this year it would cut total-and-permanent-disability cover tied to concussion, CTE, and post-concussion syndrome for AFL players from May 2026, trimming the available benefit by hundreds of thousands of dollars per player, according to Insurance Business Australia. The insurer pointed to continued uncertainty about the long-term scale of CTE risk as the reason for the pullback - uncertainty that a peer-reviewed prevalence figure of one in four is likely to reduce, even if it doesn't eliminate it.
That tension sits at the heart of underwriting this line: better data can cut both ways. It can justify tighter terms and higher premiums for the exposure that remains, or it can give carriers enough confidence in the size and shape of the risk to write it more competitively than they would under pure uncertainty. Which way the market moves may depend on what emerges from the NFL's own trial process this autumn, when internal league communications about what executives knew, and when, are expected to become part of the public record.
For life and disability underwriters, the new data adds specificity to a question that has typically been handled with broad occupational ratings for professional athletes: how much of the excess mortality and disability risk in this population is attributable to a single, now better-quantified, cause. The study's authors, writing that the disease is entirely preventable because its principal driver - cumulative head impact over a lifetime, including in youth football - is a modifiable exposure, are effectively arguing that CTE risk can be underwritten and mitigated the way other occupational hazards are, rather than treated as an unknowable outlier.
For casualty and liability underwriters covering youth and amateur leagues, the relevant number may be less the NFL's 24.5% and more the emerging pressure on assumption-of-risk defenses generally. As plaintiffs across contact sports increasingly cite population-level prevalence data rather than individual case studies, waiver language and informed-consent documentation are likely to face closer scrutiny in coverage disputes. Brokers placing athlete-specific coverage should also expect more questions from underwriters about pre-existing head-injury history, an area already under scrutiny in the loss-of-value policies written for elite college prospects ahead of the professional draft.
Read next: What is athlete loss-of-value insurance?
The NFL, for its part, said in a statement that it "continuously strives to make the game of football safer," pointing to its ongoing work on concussion protocols and player resources. The NFL Players Association called the findings "a sobering reminder that football carries real risks" and said they should prompt "a call to action across the entire football ecosystem" - language that plaintiffs' attorneys and underwriters alike are likely to be citing for some time.
