Mercury Treasury vs Brex Treasury
Last updated 2026-10-17. Rates snapshot 2026-10-16; each figure carries the provider's own as-of date and links to its source.
Mercury Treasury requires $250K across Mercury accounts and offers a government money market fund or an ultra-short bond fund. Brex Treasury has no minimum and pays a 'total treasury return' (a government money market fund plus an additional return Brex pays), tiered by total Brex balance.
What you'd earn at your balance
| Balance | Mercury | Brex |
|---|---|---|
| $100K | Not eligible (minimum: $250,000 across Mercury accounts) | 3.57% Total treasury return |
| $500K | 3.28% Gov't MMF (MRGXX) · 3.60% Ultra-short bonds (MCRYX) | 3.62% Total treasury return |
| $1M | 3.28% Gov't MMF (MRGXX) · 3.60% Ultra-short bonds (MCRYX) | 3.62% Total treasury return |
| $5M | 3.53% Gov't MMF (MRGXX) · 3.85% Ultra-short bonds (MCRYX) | 3.77% Total treasury return |
| $25M | 3.73% Gov't MMF (MRGXX) · 4.05% Ultra-short bonds (MCRYX) | 3.92% Total treasury return |
Net published yields at each balance, as the providers print them. How the tier is set:
- Mercury: Total deposits across all Mercury accounts; Treasury requires $250K
- Brex: Total Brex balance across Checking, Treasury and Vault
Side by side
| Mercury | Brex | |
|---|---|---|
| Product | Mercury Treasury | Brex Business Account – Treasury |
| Type | Gov't money market fund (MRGXX) and ultra-short bond fund (MCRYX) | Government money market fund (DGVXX) |
| Headline yield (up to) | 4.05% | 3.92% |
| Entry-tier yield | 3.28% | 3.57% |
| Yield detail | $250K–2M: 3.28% MMF / 3.60% ultra-short · $20–50M: 3.73% / 4.05% (net of fees) | 3.57% ($0–500K) · 3.62% ($500K–2M) · 3.72% ($2–5M) · 3.77% ($5–20M) · 3.92% ($20M+) 'total treasury return' (DGVXX 7-day yield 3.51% plus an additional return paid by Brex Treasury LLC; tier set by total Brex balance) |
| Yield as of | 2026-10-09 (re-checked 2026-10-17, unchanged) | unknown (not dated on page; re-checked 2026-10-17) |
| Minimum | $250,000 across Mercury accounts | None |
| Fees | 0.15%–0.60%/yr of Treasury positions (yields shown net) | No treasury transaction, monthly or account fees stated |
| Liquidity | MMF same day if by 3pm ET; ultra-short 1–2 business days (up to 4) | Same-hour (per Brex) |
| Protection | SIPC up to $500K (incl. $250K cash) via Apex Clearing; not FDIC. Checking/savings: up to $5M FDIC via sweep | Treasury: SIPC (Brex Treasury LLC), not FDIC. Separate Vault sweep: up to $6M FDIC across 24 program banks |
| Source | Mercury page | Brex page |
How to choose
- Check eligibility first. A higher top-tier rate doesn't help if your balance is below the minimum or the top tier.
- Compare like with like. A money market fund's 7-day yield, a T-Bill's yield to maturity and a bond fund's yield are different measures. See methodology.
- Mind liquidity. Keep payroll-and-vendor cash in an operating account; only move cash you won't need for a while. See where to keep startup cash.
FAQ
Which pays more, Mercury or Brex?
It depends on balance. Mercury shows the higher headline (top-tier) yield: 4.05% vs 3.92%. Brex shows the higher entry-tier yield: 3.57% vs 3.28%. See the balance table on this page for each tier.
Is Mercury Treasury FDIC insured?
Mercury: SIPC up to $500K (incl. $250K cash) via Apex Clearing; not FDIC. Checking/savings: up to $5M FDIC via sweep.
Is Brex Treasury FDIC insured?
Brex: Treasury: SIPC (Brex Treasury LLC), not FDIC. Separate Vault sweep: up to $6M FDIC across 24 program banks.
What is the minimum for Mercury and Brex?
Mercury: $250,000 across Mercury accounts. Brex: None.
How fast can I get the money back?
Mercury: MMF same day if by 3pm ET; ultra-short 1–2 business days (up to 4). Brex: Same-hour (per Brex).
All providers: rates table · current startup treasury rates · all guides
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We keep your email private and use it only for this newsletter. Every issue will have an unsubscribe link.Not financial advice. IdleCash is an independent, informational comparison. We are not a bank, broker or adviser. The comparison table is always sorted purely by the data; sponsorship never changes rank. Yields are variable, quoted as each provider advertises them, and may have changed. Securities products are not FDIC-insured and can lose value. Verify on the provider's site before acting.