Why an Unrealized Gains Tax Is Likely Coming to Your Investment Portfolio

The prospect of an unrealized gains tax represents one of the most significant policy shifts on the horizon for American investors. While initially targeting only the ultra-wealthy, historical precedent suggests this type of taxation will eventually broaden its reach to middle-class households. Understanding how we got here—and where we’re headed—is essential for anyone with meaningful investments.

The Fiscal Crisis Warning from Wall Street’s Biggest Names

The alarm bells about America’s financial trajectory are coming from unexpected quarters. Warren Buffett, speaking at Berkshire Hathaway’s annual shareholder meeting in Omaha, outlined his concerns about the government’s inability to manage its finances responsibly. Rather than fixating on the absolute size of the national debt—currently hovering at $34.7 trillion—Buffett emphasized his real worry: the fiscal deficit.

The distinction matters. While total public debt represents the cumulative obligations the government has accumulated over decades, the fiscal deficit measures the annual shortfall between income and spending. In 2024, this deficit reached $1.1 trillion, marking a $46 billion increase compared to the same period the previous year. According to reporting from The Kobeissi Letter, the federal government has been adding roughly $10 billion to the national debt each day since March 2024.

Buffett’s perspective on the likely solution is blunt: “Higher taxes are likely.”

Billionaire investor Stanley Druckenmiller echoed this concern on CNBC, articulating a concept economists call the “crowding out effect.” As governments spend excessively and interest rates climb to service that debt, available capital gets diverted away from productive investment in innovation and business growth—and toward servicing government obligations. The result is predictable: the burden must be recouped through taxation.

“They’ve spent and spent and spent,” Druckenmiller warned, “and my new fear now is that spending and the resulting interest rates on the debt that’s been created are going to crowd out some of the innovation that otherwise would have taken place.”

Understanding the Proposed Tax on Unrealized Gains

President Biden’s 2025 budget proposal introduced a concept that fundamentally challenges traditional taxation models: taxing investment gains that haven’t been realized. In practical terms, an unrealized gains tax would require you to pay taxes on paper profits—even if you haven’t sold the asset and converted those gains into actual cash.

Consider a concrete example: an investor holds Nvidia shares that have appreciated $15,000 in value. Under an unrealized gains tax, that investor would owe taxes on the $15,000 gain immediately, without ever having sold the shares or accessed the cash to pay those taxes. If Nvidia crashes the following year and the gains evaporate, the taxpayer has already paid taxes on wealth that no longer exists.

As currently proposed, this tax would impact only Americans with net worth exceeding $100 million—roughly 0.003% of the population. It’s unlikely to directly affect most individual investors or savers in the near term. The proposal also faces significant political headwinds and won’t pass in its current form this year.

However, dismissing this policy as irrelevant would be a strategic error.

The AMT Precedent: How ‘Temporary’ Taxes Become Permanent

The true lesson about government taxation comes not from what’s proposed today, but from what happened with the Alternative Minimum Tax (AMT) five decades ago.

Congress introduced the AMT in 1969 with an explicitly narrow purpose: to prevent 155 wealthy Americans—those earning more than $200,000 in adjusted gross income—from avoiding federal taxes entirely through strategic use of municipal bond holdings. The public was outraged that the rich had found legal loopholes, so lawmakers crafted what was meant to be a surgical fix.

Over the following decades, something predictable happened. As inflation eroded the purchasing power of the dollar and personal incomes climbed across the economy, more and more Americans crossed the original $200,000 threshold. The AMT’s reach expanded silently, without Congressional action or public debate. By 2010, this “tax on the ultra-wealthy” had ensnared 30 million American taxpayers—the vast majority of whom would never be considered wealthy by any objective standard.

It took the Tax Cuts and Jobs Act of 2017 to finally curtail the AMT’s scope. But consider the amount of wealth extracted from middle-class Americans during that nearly 50-year period. The mechanism was simple: a tax intended for 155 people eventually touched tens of millions because the government never updated the thresholds to account for economic growth and inflation.

Scope Creep: When Taxes Targeting the Rich Hit Everyone

This historical pattern offers a compelling blueprint for understanding the likely trajectory of an unrealized gains tax. Even if politicians genuinely intend for this tax to apply only to billionaires and hundred-millionaires, the financial pressures on government budgets virtually guarantee that the definition will eventually expand.

Forbes has already anticipated this trajectory: “A shift in tax policy towards tapping revenue streams in unrealized gains is almost certainly on the horizon. It is just a matter of degree.” The magazine notes the strategy would likely target “high-net-worth individuals and liquid assets first,” before expanding further.

Read that qualifier closely: “first.” The clear implication is that secondary targets are already being considered.

The culture surrounding taxation is also shifting. Discussions about “equitable” taxation are gaining volume in public discourse, with some policymakers and commentators arguing that middle-class Americans—particularly those earning between $150,000 and $500,000 annually—should bear a larger share of the tax burden. The Boston Review has published pieces explicitly arguing for expanding tax obligations to “the affluent,” defined as Americans in the 90th to 99th percentile of income.

The $150K Trap: Where the Real Tax Burden Lies

Here’s where the analysis becomes uncomfortable for ordinary savers and investors: the definition of who should contribute more tax revenue keeps expanding downward.

According to Census Bureau data from 2022, the median household income for a family of four stood at $114,425. Yet MarketWatch’s reporting revealed a sobering reality: families earning $150,000 annually reported they are “just getting by” when accounting for housing costs, childcare, healthcare, and the need for emergency savings. A middle-class quality of life increasingly requires six-figure incomes, yet income growth hasn’t kept pace with cost-of-living increases.

The danger isn’t merely that inflation will push ordinary Americans into whatever tax bracket gets created. The more immediate risk is that policymakers will lower the threshold directly, intentionally widening the net to ensnare increasingly ordinary households.

The Long-Term Outlook for Investors

The combination of factors—accelerating fiscal deficits, political calls for “equitable” taxation, and technological ability to track and tax investment gains—makes some form of taxation on unrealized gains increasingly probable. While the unrealized gains tax as currently proposed faces obstacles, expecting the government to simply abandon the concept is unrealistic.

For individual investors, the implications are substantial. Between inflation eroding purchasing power, fiscal deficits constraining government finances, and the mounting likelihood that unrealized gains tax concepts eventually broaden, maintaining today’s financial security will require generating additional income from investments or other sources.

The playbook is becoming clearer: government spending will continue to exceed revenues. Higher taxes will follow. And yesterday’s “taxes on the ultra-wealthy” will eventually become tomorrow’s obligations for middle-class savers and investors.