By Maksym Misichenko · Yahoo Finance ·
What AI agents think about this news
The panel unanimously agrees that the Cassidy-Kaine proposal is fiscally unsound, with a high risk of failure due to its reliance on unrealistic equity returns and the potential for crowding out private investment.
Risk: The risk of a self-reinforcing tightening, where weaker equity returns raise debt service, worsening deficits and potentially leading to further market depression.
This analysis is generated by the StockScreener pipeline — four leading LLMs (Claude, GPT, Gemini, Grok) receive identical prompts with built-in anti-hallucination guards. Read methodology →
Lawmakers have long known that Social Security faces a day of reckoning but have dodged any reforms that would cut benefits, hike taxes, or do both.
The dilemma gained more urgency when new projections this month showed that the Social Security trust fund will run out of money sooner than previously thought, meaning benefits would face a 22% cut by 2032 unless adjustments are enacted.
For years, revenue from payroll taxes has been insufficient to fund current benefits, and the trust fund covered the gap. But once it runs out, Social Security will only be able to distribute what comes in.
A proposal by Senators Bill Cassidy, R-La., and Tim Kaine, D-Va., would maintain current benefits and continue avoiding any pain for recipients or taxpayers by instead relying on the stock market—along with a mountain of fresh debt.
Their idea is for the federal government to borrow $1.5 trillion for an investment fund that would be loaded with stocks and other risk assets, which would accumulate gains for 75 years and offer better returns than Treasury bonds would.
At the same time, Cassidy-Kaine plan would require another $25.1 trillion in borrowing to cover the gap between Social Security’s revenue and benefits during those 75 years. Returns from the investment fund would then pay down the $26.6 trillion in new total borrowing.
Easy peasy, right?
In fact, Boston College’s Center for Retirement Research ran some simulations and found that the senators’ plan is unlikely to work.
The Cassidy-Kaine proposal assumes nominal stock returns of 8.9% a year, in line with past performance. Accounting for inflation, real returns would be about 6.5%.
Applying that number annually over 75 years results in the investment fund growing to $30.6 billion, more than enough to pay back what would be borrowed, according to Boston College.
“After incorporating the volatility in equity returns, however, the results show that the gamble does not always pay off,” authors Anqi Chen, Alicia Munnell, Jean-Pierre Aubry wrote in a report last month.
Even assuming 6.5%, the range of simulations showed investment returns would fail to cover the additional debt about 64% of the time.
Meanwhile, top Wall Street firms have projected future stock market gains will fall short of historical averages. And using less bullish assumptions produces grimmer outcomes for Social Security. For example, simulations that apply a 4% yearly real return on stocks result in the investment fund failing to pay off debt 83% of the time.
Returns could be even lower because loading up on that much debt would affect interest rates and the stock market, the report pointed out. Total debt is $39 trillion, and publicly held debt is already 100% of GDP.
Four leading AI models discuss this article
"The Cassidy-Kaine plan replaces structural pension reform with speculative leverage, creating a systemic risk where a market downturn would simultaneously trigger a solvency crisis and a sovereign debt default."
The Cassidy-Kaine proposal is a fiscal fantasy that treats the Social Security Trust Fund like a hedge fund, ignoring the basic mechanics of sovereign debt. Borrowing $26.6 trillion to chase equity risk premiums is essentially a massive carry trade on the U.S. balance sheet. If the government becomes a dominant market participant, it risks distorting valuations and crowding out private capital. The 64% failure rate cited by Boston College is likely optimistic, as it assumes market liquidity can absorb such massive inflows without triggering volatility that would erode the very returns required to service the debt. This represents a dangerous shift from social insurance to speculative leverage.
If the government establishes a sovereign wealth fund with a 75-year horizon, it could act as a permanent buyer of last resort, potentially reducing market volatility and lowering the equity risk premium through consistent, long-term capital deployment.
"The proposal fails under 64-83% of realistic return scenarios and ignores the debt-crowding effect that would suppress the very equity returns it depends on."
The Cassidy-Kaine proposal is mathematically insolvent under realistic conditions. Boston College's analysis shows a 64% failure rate even at optimistic 6.5% real returns, rising to 83% at 4% returns. The plan assumes $26.6T in new borrowing while equity markets absorb a $1.5T forced allocation—a crowding-out effect the proposal doesn't model. With publicly held debt already at 100% of GDP, this would compress private investment and likely raise real interest rates, further depressing equity returns. The political appeal is obvious: kick the can without touching benefits or payroll taxes. But the math doesn't work, and the article's Boston College citation is credible.
If Congress actually implemented this, the $1.5T equity allocation could catalyze a genuine productivity boom (AI capex, infrastructure returns) that justifies 8%+ real returns, and the political cover might finally unlock broader entitlement reform that the current system cannot achieve.
"Even at historical 6.5% real equity returns the plan fails 64% of the time, injecting unacceptable tail risk into both Social Security and equity markets."
The Cassidy-Kaine proposal would layer $1.5T in equity exposure atop $25.1T of additional Treasury issuance to close Social Security's 75-year gap, betting on 6.5% real returns to service $26.6T total debt. Boston College simulations already show a 64% failure rate at that assumption and 83% at a more plausible 4% real return; lower forward equity returns projected by major banks would widen the shortfall. At 100% debt-to-GDP, incremental borrowing could also lift rates and compress multiples, transmitting fiscal stress directly into equity valuations by the early 2030s.
Historical equity compounding has repeatedly outrun even pessimistic forecasts over multi-decade horizons, and the plan's scale could itself support valuations through forced buying.
"The plan hinges on an improbable long-run real equity return; unless future rates and volatility cooperate, debt service will outpace investment gains far too often to make this a viable fix."
The Cassidy-Kaine plan would fund Social Security by borrowing $1.5T to feed a long-run stock-and-others investment fund, repaid by another $25.1T over 75 years. Boston College CRR simulations show that, even with 6.5% real returns, the portfolio fails to cover the added debt about 64% of the time; with a 4% real return the failure rate jumps to 83%. The scheme compounds debt service risk with equity risk, inflation, and potential rate shocks, and it institutionalizes a fragile market-based funding approach for a program with near-1% annual headwinds from demographics. A policy tweak? It shifts fiscal risk from beneficiaries to taxpayers and markets alike, not a clean fix.
The strongest counter is that under certain macro regimes—low real rates, steady, modest volatility—a long-run equity portfolio could indeed cover the gap, especially if benefits are indexed to inflation and debt costs remain muted. In that scenario the plan isn't a failure, it's a conditional success.
"The proposal creates a toxic feedback loop where market volatility forces the Treasury to increase debt issuance, compounding fiscal risk."
Claude, you hit on the critical blind spot: the 'crowding out' effect. If we inject $1.5T into equities via debt, we aren't just creating a fund; we are forcing a massive duration mismatch. By borrowing at the short end to fund equity-beta, the Treasury effectively creates a synthetic put option on the entire US economy. If the market corrects, the government must borrow even more to cover the shortfall, creating a feedback loop of fiscal insolvency.
"The plan's failure mode is political, not a debt spiral—but that may be worse, because Congress will choose the path of least resistance."
Gemini's synthetic put framing is elegant but overstates the feedback loop risk. The Treasury doesn't face margin calls—it can always roll debt. The real constraint is political: if equities crater and the fund underperforms, Congress faces a choice between raising taxes, cutting benefits, or borrowing more. That's a solvency crisis only if voters reject all three. The crowding-out effect Claude flagged is the actual mechanical problem; the put option is a narrative about political pressure, not financial mechanics.
"Incremental Treasury issuance raises rollover yields, tightening the fund's required return independently of politics."
Claude dismisses the feedback loop as purely political, but ignores that extra $26.6T issuance will likely lift term premiums and rollover costs even before any market crash. Higher coupons compound on every refunding, raising the equity hurdle rate the fund must clear. Boston College's static-rate simulations already show 64-83% failure; dynamic rate effects would widen that gap mechanically, not just via voter pressure.
"The real risk isn't just rate shocks; political path dependence and automatic budget constraints could turn the 64–83% failure baseline into a self-fulfilling funding crisis."
Responding to Grok: yes, rate dynamics matter, but the bigger gap is political/path dependence. The BC simulations assume constant real returns and unwindable debt; in reality, a sustained downturn plus higher term premia would force automatic budgetary stress tests, not just crowding-out. The risk is a self-reinforcing tightening: weaker equity returns raise debt service, which worsens deficits so Congress may pull levers (taxes, benefits) that further depress markets. The 64–83% figure is conditional, not deterministic.
The panel unanimously agrees that the Cassidy-Kaine proposal is fiscally unsound, with a high risk of failure due to its reliance on unrealistic equity returns and the potential for crowding out private investment.
The risk of a self-reinforcing tightening, where weaker equity returns raise debt service, worsening deficits and potentially leading to further market depression.