On the surface, high-yield treasury and money market accounts look like a simple choice: pick the platform with the highest APY. But the real value isn't just the return on your cash; it's the control over it. When you need to fund payroll or seize an opportunity, the fine print on liquidity, fees, and integrations suddenly matters more than a few basis points.
This guide breaks down these critical dimensions, comparing four leading platforms: Rho, Brex, Mercury, and Ramp. Each offers a different trade-off, but Rho distinguishes itself by structuring its treasury for businesses that prioritize security, workflow automation, and strategic control over their capital.
Key takeaways
- All four platforms—Rho, Brex, Mercury, and Ramp—offer modern cash-management solutions that earn meaningful returns on idle funds.
- True value depends on more than headline APY: fee schedules, liquidity windows, and the investment structure all matter.
- Rho stands out by offering flexible options—direct ownership of U.S. Treasury bills for maximum security or the Morgan Stanley MULSX money market fund for diversification and faster liquidity—plus automation and deep ERP integrations.
What is Rho’s High-Yield Account?
Rho’s high-yield account combines high-yield investment options with automation and accounting integrations to turn cash management into a secure, efficient operation.
What does Rho’s High-Yield Account offer?
- Yield: up to 4.25% net (after 0.15%–0.60% fees).
- Minimum: $350K.
- Structure: choice of direct U.S. Treasuries or MULSX money market fund.
- Liquidity: T-Bills typically 2–3 business days; mitigated with rule-based sweeps to keep operating accounts topped up.
- Automation: rule-based sweeps between operating and treasury accounts.
- Integrations: QuickBooks, NetSuite, and more.
- Support: 24/7 live human support for all customers.
Best for: well-funded startups and established businesses prioritizing security, automation, and scalability.
What is Brex’s High-Yield Account?
Brex offers a business money market account optimized for accessibility and speed.
What does Brex’s High-Yield Account offer?
- Yield: up to 4.35%, no fees.
- Minimum: none.
- Structure: pooled government money market fund.
- Liquidity: same-hour access to funds.
- Support: general 24/7 access; expert support on premium tiers.
Best for: early-stage and lean teams that need instant access to cash with no minimums.
What is Mercury’s High-Yield Account?
Mercury targets later-stage startups, emphasizing access to institutional-grade funds from well-known managers.
What does Mercury’s High-Yield Account offer?
- Yield: up to 4.23% net (after 0.15%–0.60% advisory fees).
- Minimum: $250K.
- Structure: pooled portfolios managed by J.P. Morgan & Morgan Stanley.
- Liquidity: varies from same-day to 1–4 business days.
- Automation/Support: more digital-first; urgent phone line available.
Best for: later-stage startups with predictable cycles that value big-name managers over deep ERP automation.
What is Ramp’s High-Yield Account?
Ramp’s high-yield account extends its spend/AP platform, appealing to existing Ramp users.
What does Ramp’s High-Yield Account offer?
- APY: currently 4.64% on balances up to $500K.
- Minimum: none.
- Structure: funds held with a network of partner banks.
- Liquidity: quick access.
- Integrations/Support: deep accounting integrations; some advanced features/support behind paid tiers (Ramp Plus).
Best for: teams already embedded in Ramp who value ecosystem convenience.
Rho vs. Brex vs. Mercury vs. Ramp: A detailed comparison
1) APY, fees, and minimums
Brex and Ramp emphasize accessibility (high yields, no minimums). Rho and Mercury target capitalized businesses with higher minimums and yields stated net of fees—clearer for planning true returns.
2) Liquidity and investment structure
Brex, Ramp, and Mercury primarily use pooled funds to maximize speed. Rho uniquely offers a choice: direct T-Bill ownership for security or a money market fund for speed—plus automation to keep operations funded.
3) Integrations and workflow
Ramp and Brex integrate well but gate some automation behind paid tiers; Mercury is more manual. Rho includes ERP integrations and automated sweeps for all customers.
4) Support and operating risk
Rho includes 24/7 live human support for everyone. Brex, Ramp, and Mercury offer capable models but may tier specialist or priority access—introducing potential delays during critical moments.
High-Yield Accounts: At a glance
| Feature | Rho High-Yield | Brex High-Yield | Mercury High-Yield | Ramp High-Yield |
|---|---|---|---|---|
| APY | Up to 4.25% net (after fees) | Up to 4.35% | Up to 4.23% net (after fees) | Up to 4.64% (≤ $500K) |
| Minimums | $350,000 | None | $250,000 | None |
| Liquidity | 1–3 days (T-Bills); faster via MMF | Same-hour | Same-day to 1–4 days | Quick access |
| Structure | Direct U.S. T-Bills or MMF (MULSX) | Pooled government MMF | Pooled institutional funds | Partner-bank held funds |
| Integrations | ERP integrations & automated sweeps | Embedded in Brex suite | Limited automation | Deep integrations; some behind paid tiers |
| Support | 24/7 live human (all users) | 24/7 general; experts tiered | Digital-first | Priority support behind paid tiers |
| Best for | Security + ERP automation | Instant access & no minimums | Institutional fund management | Existing Ramp users (convenience) |
Wrap-up: Choosing the right high-yield account
If treasury is core infrastructure, Rho stands out with direct T-Bill ownership, deep ERP integrations, automated sweeps, and universal 24/7 human support. For startups that need immediate liquidity and no minimums, Brex is the most accessible. Ramp is the convenient add-on for teams already embedded in its spend/AP stack, while Mercury appeals to later-stage companies that value institutional managers and can live with variable liquidity.