Social Security Retirement Reform Impact: Who Pays and How Much?

Restoring Social Security's finances, though daunting, appears to be a solvable problem. Deciding which households absorb the cost is harder, and it is the part the current debate is least equipped to answer. 

I recently conducted some preliminary research that looked at what an across-the-board Social Security benefit cut would ask of individual workers. Among 401(k) participants earning at least $25,000, I found that fewer than one in five could replace the lost benefit through additional saving without pushing their total contributions past a quarter of pay.  

And for the vast majority of workers within a decade of retirement, the required amount was economically infeasible. It’s important to note that the various reform packages that eventually will materialize may not distribute these adjustments uniformly, which is precisely why the package itself, rather than the assumed across-the-board reduction, needs to be modeled.  

My preliminary analysis, though, took the 22% cut as given. It did not consider which reform package produced it, or whether a different package would have landed differently. 

I also submitted a statement for the record to the US Senate Committee on Finance following its hearing on Aug. 5, 2026, "Exploring Process Approaches for Addressing Social Security Solvency." The statement makes the argument that solvency should work as a constraint on reform, meaning a reform proposal either puts Social Security on a sustainable path, or it does not.  

Once proposals clear that constraint, the Morningstar Model of US Retirement Outcomes, or MMURO, can estimate how much each one would change a household’s odds of running short in retirement and by how much. 

MMURO is a participant-level microsimulation model we built that enables us to estimate how changes to the retirement system may affect retirement readiness across various demographic segments, from broad populations down to highly granular subgroups. With MMURO, we can model changes to anything from policy revisions to plan design modifications.  

Two terms are worth pinning down: solvency versus sustainable solvency. A program is solvent if it can pay scheduled benefits in full and on time. Sustainable solvency is the stricter standard used in Social Security actuarial analysis in which trust-fund reserves remain positive throughout the 75-year projection period and are stable or rising at the end of it. 

Under the 2026 Trustees Report's intermediate assumptions, the fund covering retirement and survivor benefits will run out of reserves in the fourth quarter of 2032, after which continuing program income would cover about 78% of scheduled benefits.  

So, Congress has a financing problem, and conceptually, it is not a hard one. Many combinations of higher revenue and lower benefits will close the gap. The hard part is choosing among them because arithmetic has an annoying habit of being indifferent to who bears the consequences. 

A cut applied at the same rate to every beneficiary looks admirably even-handed on a spreadsheet, but reality is messier. 

In a 2010 analysis, Craig Copeland and I modeled a 24% Social Security benefit reduction beginning in 2037 (close to, but not identical to, the 22% implied by the 2026 Trustees Report projections) and tracked its effects on retirement adequacy.  

Specifically, we measured whether a household's income and assets would cover its basic living costs along with health and long-term care expenses throughout retirement. The share of households projected to fall short rose by 0.3 percentage points for early boomers and by 5.8 percentage points for Generation X. Within Generation X, it rose by 7.2 percentage points for households in the lowest quarter of the income distribution and by 4.2 percentage points for those in the highest. 

Those estimates reflect the financing assumptions and household circumstances of 2010, so I would not present them as estimates of what a cut would do today. The pattern is what carries over. A reform’s effect depends on much more than the size of the tax increase or the benefit reduction. Age matters because younger households have more time to adjust.  

So does whether a worker has a retirement plan at all, how much has already accumulated in it, when they claim benefits, and what other income they will have. Two households with nearly identical lifetime earnings can experience the same reform differently. Equal treatment in the benefit formula does not produce equal consequences in retirement.  

MMURO can identify those differences. Take two households with similar lifetime earnings, one holding substantial 401(k) savings and decades still to work, the other with little accumulated wealth and only a few years left.  

Does a given Social Security change affect their retirement outcomes differently and, if yes, by enough to matter? 

If retirement-plan coverage, accumulated assets, birth cohort, and claiming behavior materially change how a reform affects them, then MMURO is telling policymakers something that a distributional analysis based primarily on lifetime earnings may obscure. Distributional analysis, in this context, means the standard practice of sorting households by lifetime earnings and reporting the average taxes each group pays and benefits each group receives. 

If lifetime earnings turn out to explain nearly all of the variation, the additional complexity is not justified. The objective is not to run a microsimulation because we happen to own one. A model should earn its complexity. There is also a practical question once the affected households are identified.  

For workers with time and financial capacity to adjust, the model can test whether realistic increases in saving, automatic escalation, or later retirement could materially offset the effect of a particular reform. For others, those responses may simply be insufficient. That distinction matters for plan sponsors as well as policymakers. 

Burden has no single correct definition, and the definition chosen can change the ranking. One package may lean mainly on payroll tax increases. Another on benefit reductions. A third may push more of the adjustment onto younger workers, which is what analysts mean by generational incidence.  

Each of these levers of increasing solvency will inevitably negatively affect certain demographics more than others. Whether a package looks good depends on what groups—and by how much—the policymaker is willing to have shouldered the burden.  

For that reason, the framework in my Senate Finance statement compares retirement adequacy against several measures of burden separately rather than blending them into a single score. Set the results side by side, and you get what I describe as an adequacy-versus-burden frontier. Start by eliminating every proposal that fails sustainable solvency.  

Among the survivors, estimate what each one does to retirement adequacy and set that against each measure of burden in turn. Some packages may deliver better adequacy at the same level as a particular burden measure, making them preferable on those two dimensions. Where none does, policymakers are facing a genuine tradeoff and ought to know it

Policy analysis usually gets interesting when clean answers have run out. 

One caution applies when one finding is dominant. A package that dominates one measure may not dominate another. A reform that looks better when burden is counted in benefit reductions may look worse when it is counted in payroll taxes, or in what it asks of workers now in their 30s. Claims of dominance in Social Security analysis should come with a reasonably healthy supply of footnotes. 

The financing problem requires action, and every year of delay makes the required adjustment larger and concentrates it on fewer birth cohorts.  

But restoring solvency does not tell Congress which package to choose. It only tells Congress which packages are eligible. 

The question that follows is the one worth putting real analytical resources against. Among the proposals that would put Social Security on a sustainable financial path, which ones do the best job of preserving retirement adequacy, for whom, and at what cost?  

MMURO is built to answer that, and it can answer it before a package is enacted rather than after. 

So, the ask is narrow. Any serious Social Security reform package should be scored on what it does to household retirement outcomes, not only on what it does to trust-fund balances. That will not resolve the value judgments at the center of Social Security reform. It will put the tradeoffs in front of the people casting the votes, which is where they belong.