What idle business cash actually earnsWhatidlebusinesscashactuallyearns

How this page works. Rho’s figures update from shared product rate sources and show their source-effective dates. Rho’s tier yields are net of the annual management fee (0.15%–0.60% depending on deposit tier); the separately labeled gross T-Bill figure is before that fee. Competitor figures are manually checked snapshots. Each source’s own effective date is kept separate from the date we checked it. Use the linked provider pages for their latest rates and terms.

Why you can’t compare these numbers raw

Business “yield” covers different investments and yield measures:

• Bank APY (First Citizens Innovation Banking, Bluevine, Grasshopper, Relay, Axos): interest on deposit accounts, subject to FDIC coverage limits and eligibility. Compare balance requirements, activity conditions and plan fees.

• Money market fund 7-day effective SEC yield (Mercury’s MRGXX): an annualized measure of recent fund income that includes dividend reinvestment. Mercury deducts its advisory fee to display net yield. Investment funds are not FDIC-insured.

• Ultra-short income fund 7-day current yield (subsidized) (Rho’s MULSX, IR share class): Morgan Stanley’s published annualized current yield, with Rho’s management fee deducted in the table below. MULSX is not a money market fund, and this measure is not a 7-day SEC yield.

• Ultra-short bond fund 30-day effective yield (Mercury’s MCRYX): an annualized measure including reinvestment at the recent 30-day rate, less Mercury’s advisory fee in the quoted net figure. It differs from 30-day SEC yield. The fund’s share price can fluctuate and principal is at risk.

• Annualized compounded total Treasury return (Brex): combines DGVXX income with a balance-tier additional return. The estimate assumes rates stay unchanged and payouts are reinvested for one year. It is not the fund’s 7-day yield; actual returns vary.

• T-Bill yield to maturity (Rho’s T-Bill sleeve): a rate locked when the bill is bought, backed by the U.S. government, realized if held ~13 weeks to maturity.

Compare fees and calculation methods together. Mercury and Rho deduct their respective advisory or management fees from the quoted net figures. Brex’s estimate includes a compounded additional return. Bank APYs may depend on balances, activity or paid plans. The only honest comparison is net-of-fees to net-of-fees, same instrument to same instrument, with a date on every number.

And one thing we want to be explicit about: the headline is a dated example for the U.S. T-Bill option at the lowest-fee tier, not the yield of every Rho Treasury portfolio. The table below shows how net figures change with deposit tier. Your portfolio yield depends on your allocation, the underlying investments, and fees; investment values and available yields can change.

Where the others win

Mercury publishes separate net tiers for MRGXX and MCRYX, with same-day access available for MRGXX subject to its cutoff and processing terms. Brex publishes a balance-tier return schedule starting below $500K; its compounded total-return estimate uses a different calculation from the Rho T-Bill figure. For FDIC-insured deposits, First Citizens Innovation Banking, Grasshopper, Bluevine, Relay and Axos offer the APYs and conditions shown above. Those deposit products have different protections and risks from Treasury investments. Below Rho Treasury’s $50,000 minimum, compare each provider’s opening requirements and rate conditions. All competitor figures were checked on 10/19/2026; consult the sources for current terms.

Official sources checked 10/19/2026: Mercury rates · Mercury yield methodology · Brex rates · Brex return methodology · First Citizens Innovation Banking · Bluevine · Grasshopper · Relay · Axos

What Rho Treasury is and how it works

What it is. Rho Treasury is an investment account for idle business cash, managed by RBB Treasury LLC, an SEC-registered investment adviser, and available to Rho clients that invest $50,000 or more. Your cash is invested — in your company’s name — in 13-week U.S. Treasury Bills and the Morgan Stanley Ultra-Short Income fund (MULSX).

How it works.

• Set a portfolio around your objectives — liquidity, duration, and risk. Choose a target mix across the available investments in 5% increments, based on when you expect to need the cash and your risk tolerance. Your portfolio yield reflects that allocation and the applicable fee tier; it is not a single rate shared by every client.

• It runs itself. Deposits, maturities, and dividends auto-allocate and auto-rebalance to your target. No manual bill laddering.

• The number you see is net. Rho charges a management fee of 0.15% (deposits of $20M+) to 0.60% (under $2M); every yield shown in the dashboard — and on this page — already has it deducted.

• Liquidity when you need it. Mutual fund redemptions arrive next business day; T-Bill sales settle in 2–3 business days.

• It sits next to your operating stack. Treasury lives alongside Rho checking, corporate cards, and AP in one platform — moving idle cash to work (and back) doesn’t mean another vendor.

Whose money it stays. Securities are custodied in your company’s name through Apex Clearing Corp. and Interactive Brokers LLC (registered broker-dealers, Members FINRA/SIPC) — protected by SIPC up to $500,000 per client, including $250,000 for cash claims. Rho Treasury is not a bank deposit and is not FDIC-insured; investments may lose value. FDIC insurance lives on Rho’s banking side: checking insured to $250,000 at Webster Bank, a division of Santander Bank, N.A., and Business Savings insured up to $75 million via American Deposit Management Co.’s sweep across a network of 400+ FDIC-insured institutions.

†The headline is the product U.S. T-Bill yield at Rho Treasury’s lowest-fee tier ($20M+ in total deposits; 0.15% annual fee), as of 10/31/2026. It is the annualized, unweighted mean yield to maturity across all BUY T-bill trade orders settled in the trailing seven-day window, supplied by Rho Treasury and retrieved daily, less the applicable fee. The direct T-bill figure in the comparison table is before fees; the tier matrix shows net figures after the 0.15%–0.60% annual fee. Other investments and allocations produce different yields. Yields are variable, not guaranteed, and subject to change. Rho Treasury is offered by RBB Treasury LLC, an SEC-registered investment adviser, to Rho clients investing $50,000 or more; registration does not imply a certain level of skill or training. Securities are custodied through Apex Clearing Corp. and Interactive Brokers LLC, Members FINRA/SIPC. Investments in securities are not FDIC-insured, are not bank deposits or obligations, and may lose value. Competitor rates are drawn from each provider’s published pages, verified on the dates shown, and may have changed since — confirm current rates with each provider. Banking services provided by Webster Bank, a division of Santander Bank, N.A., Member FDIC, and by Lead Bank, Member FDIC; savings sweep FDIC coverage up to $75M provided through American Deposit Management Co. and its network of 400+ FDIC-insured institutions.