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Banking

Treasury Bills vs Money Market Fund

Compare T-bills and money market funds — both ultra-short safe yield, slightly different mechanics.

Overview

Treasury bills are short-term US government debt (4 weeks to 52 weeks) bought directly through TreasuryDirect or via brokers. Money market funds are mutual funds holding short-term debt instruments. Both are very low risk; T-bills win on state-tax exemption, MMFs win on convenience.

Feature
Treasury Bills
Money Market Fund
Issuer
US Treasury
Mutual fund — usually owns Treasuries + agency + repo
Risk
Effectively zero
Very low (Treasury MMFs nearly identical risk)
State Tax
Exempt
Partial exemption — depends on holdings
Liquidity
Tradeable; redeems at maturity
Redemption typically same/next day
Yield
Tracks short-term rates closely
Slightly less (small expense ratio)
Minimum
$100 (TreasuryDirect)
$1 to $1,000 typically
Best For
Larger balances, taxable accounts in high-tax states
Convenience, brokerage cash sweep

Choose Treasury Bills when...

Buy T-bills directly when balances are large, you're in a high-tax state, and you want the highest after-tax yield.

Choose Money Market Fund when...

Use a money market fund (especially in a brokerage account) for convenience, smaller balances, and seamless cash management.

Our Verdict

For a brokerage cash position, money market funds win on convenience — auto-sweep, tradeable instantly, no need to manage maturities. For larger balances in taxable accounts (especially in high-tax states like CA, NY, NJ), T-bills directly often win on after-tax yield. Treasury MMFs split the difference but typically have small expense ratios.

Frequently Asked Questions

What is the difference between Treasury Bills and Money Market Fund?

Treasury bills are short-term US government debt (4 weeks to 52 weeks) bought directly through TreasuryDirect or via brokers. Money market funds are mutual funds holding short-term debt instruments. Both are very low risk; T-bills win on state-tax exemption, MMFs win on convenience.

When should I choose Treasury Bills over Money Market Fund?

Buy T-bills directly when balances are large, you're in a high-tax state, and you want the highest after-tax yield.

When should I choose Money Market Fund over Treasury Bills?

Use a money market fund (especially in a brokerage account) for convenience, smaller balances, and seamless cash management.

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