Last Updated on 24/08/2026
5 Black Swan Financial Trends That Emerged After 9/11
I want to focus on the kind of extreme, unexpected events that Nassim Nicholas Taleb famously called “Black Swans” in his 2007 book of the same name.
The ultimate Black Swan event occurred 25 years ago next month, when four hijacked, fuel-laden airliners were deliberately flown toward America’s financial and political centers—New York City and Washington, D.C.
But beyond the immediate human and geopolitical consequences, 9/11 also set in motion several surprising financial trends. Here are five of the most striking.
Surprise 1: From Budget Surpluses to $2 Trillion Annual Deficits
From 1998 through 2001, the U.S. government recorded four consecutive annual budget surpluses—the first four-year streak in roughly a century.
At the time, the national debt stood at around $5 trillion, and the Congressional Budget Office (CBO) projected that the debt could potentially be eliminated within a decade, by 2011.
That forecast proved wildly wrong.
Instead, the United States experienced its first four consecutive $1 trillion-plus annual budget deficits during Barack Obama’s first term, from 2009 through 2012.
Today, annual deficits are approaching $2 trillion, with little indication of meaningful relief. To put the scale into perspective, the CBO estimates that in July 2026 alone, the federal government recorded a monthly deficit larger than the annual deficits recorded in any year before the 2008 financial crisis.
That is an extraordinary transformation from where America stood in 2001.
Surprise 2: The Longest War in American History—and Perhaps More to Come
The explosion in federal spending was fueled in part by the “War on Terror” that followed 9/11.
Rather than being a single conflict, it evolved into prolonged wars in Afghanistan and Iraq. The Afghanistan war lasted from 2001 to 2021, while the Iraq War began in 2003 and formally ended in 2011.
According to the U.S. Department of Defense, the direct cost of those wars launched during George W. Bush’s first term reached at least $1.47 trillion—far above the estimates offered by then-Vice President Dick Cheney in March 2003.
Broader estimates are even more staggering. According to Costs of War research, the United States has spent more than $8 trillion on post-9/11 wars and military operations across at least 85 countries, with the total economic burden potentially reaching $10 trillion to $14 trillion once veterans’ care and interest costs are included.
The irony is particularly striking in Afghanistan. The central objective was to find Osama bin Laden, the mastermind behind 9/11. Yet he remained at large for another decade before being discovered in Pakistan.
The result was a 20-year war whose costs vastly exceeded what most Americans could have imagined in September 2001.
And now, with tensions involving Iran, the possibility of additional military commitments remains an uncomfortable question.
Surprise 3: The “Free Money” Era and the Rise of Modern Monetary Theory
Another extraordinary development emerged from the aftermath of the financial crisis.
To support a weakened economy, the Federal Reserve adopted a Zero Interest Rate Policy (ZIRP) and launched multiple rounds of Quantitative Easing (QE).
For roughly seven years, the federal funds rate remained between 0% and 0.25%.
Under Fed Chairman Ben Bernanke, policymakers were determined to avoid the deflationary mistakes of the Great Depression. The Fed instead targeted approximately 2% inflation while using extremely low interest rates and large-scale asset purchases to inject liquidity into the financial system.
The result was an unprecedented monetary environment in which borrowing became extraordinarily cheap and liquidity appeared almost limitless.
It resembled an American experiment in what later became popularly associated with Modern Monetary Theory (MMT): enormous fiscal spending supported by extraordinarily accommodative monetary policy.
When the Fed eventually began raising rates during Donald Trump’s presidency, financial markets pushed back hard. The sharp market selloff in late 2018 helped demonstrate just how dependent markets had become on cheap money.
Surprise 4: Regulations Designed to Prevent Crises Created New Risks
The post-9/11 era also produced a sweeping expansion of government regulation and financial oversight.
Following the 2008 financial crisis, the Dodd-Frank Act introduced extensive new rules designed to reduce systemic risk and prevent another financial meltdown.
But financial markets have a habit of adapting.
As traditional banks and financial institutions faced tighter restrictions, capital and risk-taking increasingly migrated toward less-regulated areas of the financial system.
The growth of private funds and other alternative investment vehicles illustrates the problem. Investors seeking higher returns can still find highly leveraged or high-interest opportunities outside the most heavily regulated parts of the financial system.
The lesson is uncomfortable but familiar:
Regulation can change where risk lives without necessarily eliminating the risk itself.
You cannot legislate away human greed, excessive optimism, or reckless risk-taking. When one door closes, financial innovation often finds another.
Surprise 5: The Stock Market Kept Climbing Anyway
And then comes the biggest positive surprise.
Despite terrorism, two prolonged wars, enormous fiscal deficits, the 2008 financial crisis, unprecedented monetary intervention, rising regulation, geopolitical turmoil and repeated market shocks, U.S. stocks continued to climb dramatically after 9/11.
The gains have not always represented cheap valuations, and there have certainly been painful crashes along the way. But the long-term direction has remained remarkably resilient.
That resilience offers a reminder of Adam Smith’s famous observation in 1778 that “there is a lot of ruin in a nation.”
Britain survived the setbacks that followed the American victory at Saratoga. It survived the devastation of World War II. And the United States absorbed the enormous shocks of 9/11 and everything that followed.
Yet its economy continued to innovate, companies continued to generate profits, and investors continued to participate in the growth of American enterprise.
That may be the biggest Black Swan of all: despite everything thrown at it since September 11, 2001, the American economic machine kept moving forward.
Leave a Reply