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Saving up cash feels safe and productive. But that feeling can eventually become a trap.

Excess cash kept in traditional checking or savings accounts isn’t just sitting still. It's actively losing ground to inflation. High-yield savings accounts (HYSAs) can return 3% to 5%, surpassing inflation and far outpacing the 0.1% to 0.3% of a typical checking or savings account. But even high-yield cash can pose a trap for savers with long-term goals. This analysis puts a number on the cost of cash, charting the gap between what a dollar earns sitting in a savings account over 30 years and what it earns invested in a diversified IRA. On a single $10,000 deposit, that gap reaches nearly $27,500 by year 30. On a $50,000 excess cash position, it exceeds $131,000.

$131,000+

The potential cost of keeping $50,000 in cash over 30 years

Key takeaways

The gap between cash and investing nearly doubles every decade. At year 15 the difference is $30,000. By year 30 it exceeds $131,000.

A wave of maturing CDs in 2026 creates a critical decision point. Many will auto-renew at a fraction of their locked-in rate and account holders may have as little as 7–10 days to redirect funds.

Keeping up with inflation isn't the same as building wealth. A 4% HYSA outpaces a traditional savings account, but still trails a retirement account by nearly $27,000 on a single $10,000 deposit.

Analysis

Sitting on excess cash can cost you

Post-pandemic interest rate hikes have left Americans holding near record levels of household cash. The most recent federal data shows a combined $14.0 trillion¹ savings accounts, certificates of deposit, and money market funds.

The data shows that the Fed’s 2022 rate hikes encouraged households to stockpile their savings. In the three years that followed, assets held in money market fund shares accelerated over 73%².

But while record-level cash yields offered a rare chance to earn while limiting risk, these lucrative returns on cash were still not the best home for savings. In 2023, the same year some saw as much as 5% back on cash, the S&P 500 returned over 26%.

Two scenarios: the price tag of “safety”

There may be an opportunity cost of keeping more than an emergency fund in the bank. While cash positions are known to be “safe” due to FDIC insurance, PensionBee’s modeling illustrates the long-term cost of excess cash.

Consider a saver who redirects $50,000 in excess cash into retirement accounts, compared to one who keeps their balance in an HYSA.

Table 1: Retirement Account vs. High-Yield Savings: 30-Year Projection

(This analysis models two scenarios over a 30-year period beginning with a $50,000 excess cash position. Scenario A assumes the full balance remains in a HYSA earning a fixed 4% APY. Scenario B assumes the balance is redirected into retirement accounts over two years — $30,500 in year one and $19,500 in year two — earning a fixed 7% annual return with a 0.85% management fee applied. Both scenarios assume no additional contributions or withdrawals. Fixed rates of return are used for illustrative purposes only; actual returns will vary.)

For excess cash sitting idle with no immediate purpose, the cost of inaction compounds quietly and significantly.

Over 30 years, the retirement account turns $50,000 into nearly $300,000 — roughly 6x the original deposit. The HYSA, by comparison, grows to just over $162,000. The gap widens steadily over decades in the market. At year 15, there is roughly a $30,000 gap between the two account types. By year 30, the gap totals $131,000.

Tax differences may widen the gap further, beyond what the modeling shows.

Interest earned in an HYSA is taxed at the saver's ordinary income tax rate. $10,000 in the bank would generate $400 in interest a year with 4% APY. At an illustrative 22% tax rate, the saver would owe $88 in taxes that year. The costs are direct and indirect: money paid in taxes each year leaves less behind to compound over time. Traditional 401(k)s and IRAs work differently. Both accounts are funded with pre-tax dollars, deferring taxes entirely until retirement, leaving more to work for longer.

For many savers, a HYSA balance growing from $50,000 to $162,000 may look like a win. And in isolation, it is. But when measured against inflation, a 4% APY roughly preserves purchasing power rather than building it. The HYSA saver isn't falling behind in any obvious way, but by staying in cash may end up with half as much wealth after 30 years. This is precisely what makes “cash drag” so easy to overlook.

While HYSAs offer 10x higher returns than a traditional bank account, a CNBC study found that a majority of Americans (82%) don’t utilize them. The scenario below considers the 30-year return differential between three account types: a traditional savings account, an HYSA, and a retirement account.

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Table 2: $10,000 Investment Growth Across Account Types (30 Years)

(This analysis models the 30-year growth of a $10,000 deposit across three account types. The traditional savings account assumes a fixed 0.39% APY. The HYSA assumes a fixed 4% APY. The retirement account assumes a fixed 7% annual return with a 0.85% management fee applied. All three scenarios assume no additional contributions or withdrawals. Fixed rates of return are used for illustrative purposes only; actual returns will vary.)

A single $10,000 deposit in the retirement account grows to nearly $60,000 over 30 years, a near $49,000 surplus compared with the same deposit sitting in a traditional savings account. As compound interest accelerates, the retirement account balance nearly doubles every 10 years. Both cash accounts drag in comparison.

The $10,000 kept in the traditional savings account struggles to keep up with inflation. Major banks offer interest rates as low as 0.01%. PensionBee assumed funds earned the current national savings interest rate of 0.39%, but even a slightly higher yield did little to offset the effects of inflation. Under a conservative 30-year inflation rate of 2.4%³, the balance lost nearly half of its future purchasing power. After adjusting for inflation, $11,239 in 30 years will have the same purchasing power that $5,300 secured today, leaving the account holder $4,700 short of where they started.

While the HYSA represents a meaningful middle ground, it is no substitute for long-term wealth building. At roughly $32,000 after 30 years, the HYSA outpaces inflation and far outpaces traditional savings accounts, yet still trails the retirement account by $27,000–nearly 3x the original deposit.

The CD maturity hazard

An estimated $1.6 trillion in Certificates of Deposit (CDs) are set to mature this year, many of which locked in peak rates in 2024. Many CDs are set to auto-renew, meaning a 4.5% CD could automatically roll over at standard rates which have no legal minimum. While current 1-year CD averages hover around 2-3%, CDs have historically paid as little as 0.1%. When CDs mature, account holders may have as little as 7–10 days to act before they are locked in to current rates

A wave of maturing CDs in 2026 presents savers with a critical decision point.

Conclusion

While the majority (54%) of Americans cannot cover three months of living expenses, others have tens of thousands sitting in standard bank accounts. Savers with maturing CDs may find a markedly different interest rate environment in 2026. What they do next may make all the difference for future security.

For cash with no immediate purpose, the bank may be the most expensive place to keep it.

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About PensionBee

PensionBee (LON:PBEE; OTCQX:PBNYF) is a leading retirement savings provider, helping people easily consolidate, manage, and take control of their retirement savings. The company manages over $10 billion in assets and serves 315,000 customers globally, with a focus on simplicity, transparency, and accessibility. PensionBee offers Traditional, Roth, SEP, and Safe Harbor IRAs with ETF-backed portfolios that include SPY and MDY from State Street Investment Management, one of the world’s largest asset managers. PensionBee is publicly traded on the London Stock Exchange (PBEE) with U.S. shares available on OTCQX (PBNYF).

Notes

Investing involves risk.

The information and data set out above, including any projections for investment returns and future performance, is provided solely for informational and educational purposes and should not be relied upon for making financial decisions. Nothing presented here constitutes tax, legal, financial or investment advice. This information does not take into account the specific financial, legal or tax situation, objectives, risk tolerance, or investment needs of any individual investor. All information provided is compiled from publicly available data and research at the time of posting or PensionBee privately commissioned research obtained through third party survey providers. Images, figures, and projections used are derived from the data described, are provided for informational and marketing purposes only and do not represent actual customer returns. Projections and forecasts are based on assumptions and current market conditions, which are subject to change. This information, and any associated customer testimonial or third party endorsement, does not constitute an offer, solicitation, or recommendation to buy or sell any securities or investments. Your investment is at risk. Past performance is no guarantee of future results. PensionBee is not liable for any losses or damages arising from the use of this information.

Footnotes

1. Federal Reserve Financial Accounts of the United States (Z.1), Table B.101.h, Q4 2025 (published March 19, 2026). Comprises $8.92T in time deposits and short-term investments and $5.08T in money market fund shares.

2. See footnote 1. Based on year-end values of $2.9T (2022) and $5.1T (2025), with peak year-over-year growth of 31.6% in 2023.

3. Federal Reserve Bank of Cleveland, 30-Year Expected Inflation, FRED, Federal Reserve Bank of St. Louis. https://fred.stlouisfed.org/series/EXPINF30YR

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Why your high-yield savings account may be riskier than you think