The federal tax exemption for municipal bond interest has been the bedrock of the $4.4 trillion muni market for over a century. It traces its origins to the Revenue Act of 1913 and has survived every major overhaul of the tax code since. When the One Big Beautiful Bill Act was signed into law on July 4, 2025, that exemption survived — a significant relief after months in which its elimination was genuinely on the table. House Ways and Means Committee documents had floated ending the exemption as part of a menu of options to fund $4.5 trillion in tax cuts. The lobbying effort to protect it was intense, bipartisan, and ultimately successful. The muni market exhaled.
But “survived for now” and “permanently settled” are not the same thing. Advisors with high-net-worth clients in meaningful muni allocations should understand why the question isn’t closed, and what the relevant risk factors look like going forward.
Start with the fiscal arithmetic. The One Big Beautiful Bill Act, even with the exemption intact, is projected to add $3.4 trillion to the national debt over ten years. The federal government scores the muni tax exemption as approximately a $250 billion cost over the same period — revenue that Washington doesn’t collect because muni interest is excluded from taxable income. Every time Congress returns to the business of finding offsets for tax cuts or new spending, that $250 billion is sitting on the table as a theoretical revenue source. The exemption didn’t get eliminated in 2025 because the political resistance was overwhelming — but the underlying fiscal pressure that put it on the menu in the first place hasn’t gone away.
The political dynamics are worth understanding in some detail. The muni exemption has defenders across party lines because state and local governments of both red and blue states depend on tax-exempt borrowing to fund essential infrastructure. The U.S. Conference of Mayors has calculated that eliminating the exemption would raise borrowing costs by $832 billion between 2026 and 2035, effectively adding roughly $6,500 in higher taxes and service charges to every American household over that period. More than 75% of the country’s public infrastructure — schools, hospitals, roads, water systems — is financed by state and local governments using tax-exempt bonds. That constituency is large, geographically broad, and politically engaged. It has historically been enough to protect the exemption, and the bipartisan advocacy that mobilized in 2025 made a strong case.
At the same time, the threat calculus can shift quickly. Bond Buyer analyst Tom Kozlik flagged that if a second reconciliation bill materializes and Congress again needs to find offsets, the tax exemption could return as a serious consideration. “If the 2026 legislation does rise and if it does end up being a big, sweeping piece of legislation, and people start talking about serious change, there could be a larger threat to the tax exemption,” Kozlik noted. The Federal Reserve Chair’s term is also expiring, adding a layer of monetary policy uncertainty that could complicate the fiscal environment further.
There’s also a subtler risk that often gets overlooked: state tax conformity. Many states conform their tax codes to federal law, meaning state-level tax policy follows federal changes. If Washington were to modify the federal exemption — even partially — states would face choices about whether to maintain their own exemptions independently. Some might. Others, facing budget pressures from Medicaid cuts and reduced federal transfers, might not. The result could be a patchwork of state-level treatment that complicates the after-tax math for clients with multi-state holdings.
What does all of this mean practically for advisors? Not that clients should reduce muni exposure preemptively — the exemption is intact, the market is functioning, and the political barriers to changing it remain substantial. What it does mean is that the muni allocation deserves the same active monitoring as any other material portfolio position. For clients who hold munis specifically because of the tax exemption, understanding the policy backdrop — and having a contingency view of what you’d do if the exemption were modified — is part of responsible portfolio management. The conversation is also a natural way to demonstrate to clients that you’re watching things they aren’t watching themselves.
