Every January since 2017, the TIAA Institute and the Global Financial Literacy Excellence Center have asked a nationally representative sample of American adults the same 28 personal finance questions. The questions cover eight areas: earning, spending, saving, investing, borrowing, insuring, understanding risk, and finding good financial information. It’s designed to be a consistent yardstick, not a one-off snapshot, and that consistency is exactly what makes the 2026 result so hard to explain away.

This year, U.S. adults answered only 47 percent of those 28 questions correctly — the weakest showing in the index’s ten-year history. The decline wasn’t concentrated in one obscure corner of personal finance either; scores fell across five of the eight domains the survey tracks. For a country where financial decisions — mortgages, retirement accounts, credit cards, student loans — are almost entirely left to individuals to navigate, that’s a genuinely significant data point.

What makes this decline notable isn’t just the single-year drop — it’s what’s happening at the bottom of the distribution. The share of adults who could only answer seven or fewer of the 28 questions correctly, essentially the group with very low financial literacy, has grown from one in five adults in 2017 to one in four in 2026. The average score is being pulled down by a genuinely growing pool of people with minimal financial knowledge, not by everyone drifting slightly lower together.

Average national scores hide how unevenly financial knowledge is actually distributed. Education is one of the sharpest dividing lines in the data: adults with a bachelor’s degree or higher answered 61 percent of index questions correctly, compared with just 30 percent among adults without a high school diploma — a full 31-point spread on the exact same test. Formal financial education makes a measurable difference too, with people who received it scoring about 13 percentage points higher than those who didn’t.

Generational gaps show up just as clearly. Gen Z adults post the lowest scores of any age group tracked in the index, averaging well below the national mean, with a large share landing in that same low-knowledge bottom tier. That’s a meaningful finding given how much of Gen Z’s financial life — student loans, gig income, first investments — is unfolding right as they’re entering the workforce with the shakiest foundation of any generation measured.

The gap isn’t just what people don’t know. It’s who has never been taught, versus who has — and that line tracks almost exactly with education and income.

This isn’t an abstract knowledge gap — it shows up as real money leaving real households. Survey-based estimates put the average individual cost of financial mistakes tied to low literacy at roughly $948 a year, with a meaningful share of people reporting losses of $2,500 or more. Scaled across the population, these losses have been estimated to exceed $246 billion annually, driven by ordinary, everyday missteps: overdraft fees, high-interest borrowing, under-saving for retirement or emergencies, and late payments that could often have been avoided with a clearer understanding of how the numbers work.

One recurring finding across these surveys is that the single most poorly understood concept is how debt compounds over time — meaning many people underestimate exactly how fast a credit card balance or a payday loan can grow if it isn’t paid down quickly. That single gap in understanding sits behind a disproportionate share of the financial damage measured every year.

The most direct lever for closing this gap has always been education, and on that front, the picture in 2026 is genuinely mixed. As of this year, 30 states now require a standalone personal finance course for high school graduation — a real expansion from where the country stood even a few years ago. But that leaves a meaningful number of states where personal finance still isn’t a guaranteed part of a student’s education, and access within states that do require it isn’t uniform either.

Where formal instruction is missing, informal sources fill the gap — and not always well. Family remains one of the most commonly cited sources of financial knowledge, but a notable share of younger adults, Gen Z in particular, now point to social media as a primary source of financial information, well above the rate seen in the general population. That matters because social media financial content varies enormously in quality, and a knowledge gap filled by an inconsistent source doesn’t necessarily close the gap — it just changes what fills it.

National policy moves slowly, but individual financial literacy doesn’t have to wait for a curriculum mandate to catch up. The domains where the index shows the steepest average weaknesses — compounding debt, insurance basics, and assessing risk — are also some of the most learnable in a single afternoon, without needing a course or a credential.

A decade of measuring the same 28 questions was never meant to produce a flat or declining line — it was meant to show progress. Instead, 2026 shows a country where financial knowledge is not just insufficient on average, but increasingly concentrated among people who already had the most access to education and resources in the first place. Closing that gap nationally will take policy and classrooms. Closing it personally can start with something much smaller: learning the one or two concepts, like how debt actually compounds, that the data says most people are getting wrong.