High-Yield Savings Account Comparison

American Express vs. Zynlo Bank

Compare rates, requirements, and features side-by-side to find the best option for you.

Analysis by Aviel Fahl
Updated December 6, 2025
Advertising Disclosure: We may earn a commission from partner links.

American Express

High Yield Savings Account

3.40%
APY
Dec 6, 2025
FDIC InsuredNo MinimumsGreat iOS App
Show Fine Print & Trends

Zynlo Bank

Tomorrow Savings Account

4.05%
APY
Dec 6, 2025
FDIC InsuredLow MinimumsGreat iOS App
Show Fine Print & Trends

Market Reality Check

Both of these banks offer rates below the current top tier. The best rates we track are currently above 4.25% APY.

See Top Rates

Comparison Analysis

Comparing American Express vs. Zynlo Bank

Updated: Dec 6, 2025

Why American Express?

  • Higher rated iOS app (4.9 vs 4.0)

Why Zynlo Bank?

  • Higher potential APY (4.05% vs 3.40%) on all balances

— Key Feature Differences —

Better Returns at $10,000
Zynlo Bank

Zynlo Bank's Tomorrow Savings Account earns more on smaller deposits (approx. $405 vs $340/yr).

Better Returns at $25,000
Zynlo Bank

Zynlo Bank's Tomorrow Savings Account pulls ahead with larger amounts (approx. $1013 vs $850/yr).

Best for Simplicity
Zynlo Bank

Zynlo Bank's Tomorrow Savings Account offers 4.05% APY with no bundling, direct deposit requirement or caps.

Best Mobile App Experience
American Express

American Express offers an iOS app rated 4.9 (vs. 4.0) and Android app rated 3.6 (vs. 3.5)

Shared Benefits

Both offer monthly maintenance-free account options Available Nationwide Available to New & Existing Customers
The Bottom Line

Over a 1-year period, Zynlo Bank's Tomorrow Savings Account pays $65 more interest on a $10,000 balance than American Express's High Yield Savings Account.

American ExpressZynlo Bank
Automated Data Audit

Executive Summary

Zynlo Bank's Tomorrow Savings Account offers a competitive APY of 4.05%, making it the winner in this comparison. This online-only account requires a minimum deposit of $10 and has no maintenance fees, providing better returns for both smaller and larger deposits. In contrast, American Express features a High Yield Savings Account with an APY of 3.40%, which, while offering a solid return, is lower than that of Zynlo Bank. American Express does not require a direct deposit and has no minimum balance, but its APY is significantly less than Zynlo's. Both banks provide a user-friendly online experience, with Zynlo Bank noted for its simplicity.

Analysis generated based on current Banksparency database records

* AI-generated content provided for informational purposes only. Accuracy is not guaranteed; always verify details with the provider.

Top Market Contenders

See who beats both American Express and Zynlo Bank.

Compare All High-Yield Savings Accounts
Pibank
Pibank Savings
FDIC InsuredNo Minimums
4.60% APY
+0.55% vs Zynlo Bank
Better Rate
Neighbors Bank
Neighbors Savings Account
FDIC InsuredNo MinimumsGreat Android App
4.50% APY
+0.45% vs Zynlo Bank
Better Rate
Axos Bank
Axos ONE
FDIC InsuredNo MinimumsGreat iOS AppGreat Android App
4.31% APY
+0.26% vs Zynlo Bank
Better Rate
FeatureAmerican ExpressZynlo Bank
APY
3.40%
Verified: 12/6/2025
↘︎ 0.10%90d Change
4.05%
Verified: 12/6/2025
↘︎ 0.30%90d Change
Product NameHigh Yield Savings AccountTomorrow Savings Account
Minimum Deposit$0$10
Min. Balance for APY$0$0.01
Monthly Fee$0$0
Branch AccessNoneNone
Account Type
Online Only
Online Only
Direct Deposit Req.NoneNone
Checking BundleNoNo
Mobile Apps
iOS4.9
Android3.6
iOS4.0
Android3.5
BBB RatingFA+
Next Steps

Savings Comparison

Calculations based on current APY.
$
$

Zynlo Bank earns $416.5 more than American Express.

American Express

High Yield Savings Account

3.40% APY

Savings Breakdown

  • Interest Earned
    +$2,050.50(10.2%)
  • Total Contributions
    $13,000
  • Initial Deposit
    $5,000

Projected Balance

$20,050.50

Effective APY
3.40%

Zynlo Bank

Tomorrow Savings Account

4.05% APY

Savings Breakdown

  • Interest Earned
    +$2,467.00(12.1%)
  • Total Contributions
    $13,000
  • Initial Deposit
    $5,000

Projected Balance

$20,467.00

Effective APY
4.05%

The Banksparency Savings Calculator provides estimated savings growth based on user input and our latest data.

📈 Compare Savings Rates Over Time

Historical Performance

Last 9 Months Analysis
MetricAmerican ExpressZynlo Bank
High Yield Savings AccountTomorrow Savings Account
Current APY
3.40%4.05%
Trend
Stable Stable
Velocity (bps/mo)
-3.0-2.6
Days Since Change
1014
9-Month High
3.70%4.35%
9-Month Low
3.40%4.05%
Adjustments / Mo
0.340.23
Volatility Score
0.0240.022
How to read these metrics(Click to expand)

Trends & Velocity

  • Trend: The general direction of the rate over the analyzed period. Useful for spotting if a bank is currently aggressive or pulling back.
  • Velocity (bps/mo): Speed of change. A high positive number means they raise rates quickly. 10 bps = 0.10%.
  • Adjustments/Mo: "Twitchiness." High frequency means the rate changes constantly; low frequency means it's stable.

Risk & Range

  • High/Low: The absolute ceiling and floor of the rate during the 265-day window.
  • Volatility Score: Lower is better for predictability. It indicates how wildly the rate swings relative to its average.
  • Days Since Change: If this number is high (e.g., >90), the rate is very sticky. If low, it changed recently.

More Comparisons

Compare American Express' APY of 3.40% with other banks
Bank PairCompetitor APYMin Deposit
American Express vs Ally Bank3.30%$0
American Express vs Axos Bank4.31%$0
American Express vs Bank of America0.01%$100
American Express vs Barclays4.00%$0
American Express vs Bask Bank3.90%$0
American Express vs BMO Alto3.25%$0
American Express vs BrioDirect4.00%$5,000
American Express vs Capital One3.40%$0
American Express vs Chase Bank0.01%$0
American Express vs Chime3.50%$0
American Express vs CIT Bank3.75%$100
American Express vs Citibank3.30%$0
American Express vs Citizens Access™3.35%$0.01
American Express vs Climate First Bank4.21%$50
American Express vs Discover Bank3.40%$0
American Express vs Elevault4.08%$0
American Express vs EverBank4.05%$0
American Express vs Fitness Bank4.75%$100
American Express vs FNBO Direct3.00%$1
American Express vs Forbright Bank4.00%$0
American Express vs FVCbank3.85%$500
American Express vs GO2bank4.50%$0
American Express vs Ivy Bank4.25%$2,500
American Express vs LendingClub4.20%$0
American Express vs Marcus by Goldman Sachs3.65%$0
American Express vs Neighbors Bank4.50%$0
American Express vs Newtek Bank4.35%$0.01
American Express vs Openbank4.20%$500
American Express vs Peak Bank4.20%$100
American Express vs Pibank4.60%$0
American Express vs PNC3.53%$0
American Express vs Presidential Bank4.00%$5,000
American Express vs Quontic Bank3.75%$100
American Express vs Salem Five Direct3.71%$10
American Express vs Santander Bank0.01%$25
American Express vs SoFi Bank4.30%$0
American Express vs Synchrony Bank3.65%$0
American Express vs TIMBR4.40%$1,000
American Express vs UFB Direct3.71%$5000
American Express vs Valley Direct4.10%$1,000
American Express vs Varo Bank5.00%$0
American Express vs Vio Bank4.16%$100
American Express vs Wealthfront4.15%$0
American Express vs Wells Fargo0.05%$25
Compare Zynlo Bank's APY of 4.05% with other banks