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PMMF vs VUSB

iShares Prime Money Market ETF

PMMFBNYSE

Vanguard Ultra-Short Bond ETF

VUSBACboe

Overlap

Expense ratio

VUSB −0.10pt a year

PMMF0.20%VUSB0.10%

Avg volume · 30D

VUSB 13.1×the volume

PMMF150KVUSB1.97M

PMMF vs VUSB Performance

Oct 31, 2025 – Oct 30, 2026

+2.7%PMMF+3.7%VUSB

Oct 31, 2025 to Oct 30, 2026. PMMF +2.7%. VUSB +3.7%. Use the arrow keys to read each point.0%1%2%Oct 2025Mar 2026Oct 2026
Expense ratio
PMMF 0.20%
VUSB 0.10%, better
Fund size
PMMF $796M
VUSB $9.9B
1Y total return
PMMF +2.7%
VUSB +3.7%, better
Yield (12M)
PMMF 4.08%
VUSB 4.27%, better
Holdings
PMMF 249
VUSB 1348
Avg volume (30D)
PMMF 150K sh
VUSB 1.97M sh, better
NAV per share
PMMF $100.28
VUSB $49.62
52W range

ETF.net Grade

PMMF: Cost 38, Risk 68, Mission 69, Tradability 73, Holdings 48, Durability 66. VUSB: Cost 84, Risk 53, Mission 100, Tradability 66, Holdings 90, Durability 89.
Pillar letters and Scores for PMMF, VUSB, with each pillar’s weight
PillarPMMFVUSB
Cost30% weightD38A84Higher
Mission25% weightB69A100Higher
Risk15% weightB68HigherC53
Tradability15% weightA73HigherB66
Holdings10% weightC48A90Higher
Durability5% weightB66A89Higher

Rank among Cash & Ultra-Short Income funds

How we build Categories ›
Same Category. Both funds are graded against the same funds, so their Grades compare head to head.

Same Category. PMMF and VUSB are both graded against the same 78 Cash & Ultra-Short Income funds, so their Grades compare head to head.

Cash & Ultra-Short Income⁠

Category · 78 funds
See all 78 ›

VUSB ranks 3rd and PMMF 44th of 78 funds in the Cash & Ultra-Short Income Category.

  1. Rank 1AICSHiShares Ultra Short Duration Bond Active ETFScore 85
  2. Rank 2ACLIPGlobal X 1-3 Month T-Bill ETFScore 82
  3. Rank 3AVUSBVanguard Ultra-Short Bond ETFScore 81
  4. Rank 4ATBLLInvesco Short Term Treasury ETFScore 80
  5. Rank 44BCSHPiShares Dynamic Short-Term Active ETFScore 57
  6. Rank 44BPMMFiShares Prime Money Market ETFScore 57
  7. Rank 46BGMMFiShares Government Money Market ETFScore 56

Our read on each fund

ETF.net Research

PMMFBiShares Prime Money Market ETF

VUSBAVanguard Ultra-Short Bond ETF

In short

PMMF Money market discipline in an ETF shell. PMMF runs a short-term credit portfolio under the SEC's strict Rule 2a-7 money fund rules, pays income monthly, and trades on an exchange during the day.

VUSB Vanguard's first actively managed bond ETF, run by its in-house fixed income team and priced at 0.10%. It holds investment-grade paper maturing inside two years: a step past a money fund, well short of a real bond fund.

Stated mandate

PMMF The fund seeks current income consistent with liquidity and principal stability while providing intraday trading flexibility.

VUSB The fund seeks current income with limited price volatility while investing in diversified high- and medium-quality fixed-income securities. It expects to maintain a dollar-weighted average maturity of 0–2 years.

Why people hold it

  • PMMF Held to Rule 2a-7, the SEC's money market rulebook, for credit quality, maturity and liquidity, with daily portfolio disclosure.blackrock.com
  • Prime, not government-only. It buys short-term corporate credit instead of sticking to Treasury and agency paper, spread across roughly 120 positions.blackrock.com
  • What it holds lines up with what it promises: current income with liquidity and principal stability, plus intraday trading. Monthly distributions.
  • The 0.20% fee sits right at the median for cash-alternative funds, so the ETF wrapper doesn't carry a novelty premium.
  • VUSB At 0.10%, it costs half the typical ultra-short bond ETF and undercuts the other leaders in the group: SHV, PULS, FLDR and DUSB all charge 0.15%.
  • Active, not adventurous. The managers buy investment-grade bonds (A3-or-better high quality plus BBB-tier medium quality) and hold average maturity to zero-to-two years.vanguard.com
  • Income lands monthly, sourced from roughly 170 bonds, so no single issuer drives the outcome.
  • A multi-billion-dollar fund that trades actively, and the same portfolio team also runs a similar Vanguard ultra-short fund.vanguard.com

Worth knowing

  • PMMF Cheaper parking spots exist: ICSH at 0.08% and JPST at 0.18%. Both are ultra-short bond funds, though, not 2a-7 money market funds.
  • Shares change hands at a market price driven by supply and demand as well as NAV, which is a different experience from a traditional money fund account.dividend.com
  • Prime paper carries issuer credit risk that Treasury-only cash funds sidestep. Launched in 2025, so its record is still short.blackrock.com
  • VUSB This is not a money market fund. No fixed $1 share price, and the market price can trade above or below the value of the holdings.vanguard.com
  • The mandate allows BBB-tier credit, a notch of risk a Treasury-only neighbor like SHV doesn't take.vanguard.com
  • Bonds this short reprice with short-term rates, so the monthly payout drifts up and down instead of holding a set level.vanguard.com

Full PMMF profile⁠

Full VUSB profile⁠

PMMF vs VUSB Holdings

How we measure overlap

Each holding counts at its smaller weight in the two funds, summed over the full Holdings. Sector, country and asset class use the same rule on each fund’s split. Cash, FX and derivative lines stay out of the counts. Two bond funds get no overlap figure.

PMMF vs VUSB Cost

Overpaying PMMF vs VUSB

$2,049

On $10,000 over 30 years. 7% growth a year before fees, expense ratio only.

  • PMMF 0.20%

    $4,155

  • VUSB 0.10%

    $2,106

$10,000
30 years

Cost over time

  • PMMF 0.20%
  • VUSB 0.10%
  • Overpaying
One line per fund, from year 0 to year 30. Use the arrow keys to read each point.$0$1K$2K$3K$4K$5K051015202530PMMF $4,155VUSB $2,106

Year by year

YearPMMFVUSBOverpaying
10$365$183$182
20$1,421$717$704
30$4,155$2,106$2,049

Expense ratio

  • 0.20%PMMF
  • 0.10%VUSB, cheaper
  • Middle half of Cash & Ultra-Short Income funds
  • Median 0.18%

VUSB 13th cheapest of 78 funds

PMMF 45th cheapest of 78 funds

PMMF vs VUSB Dividends

Last 12 months to Oct 30, 2026
Yield (12M)
PMMF 4.08%
VUSB 4.27%, better
Payout (12M)
PMMF $4.09
VUSB $2.12
Last payment
PMMF $0.07
VUSB $0.18
Ex-dividend
PMMF Oct 28, 2026
VUSB Oct 1, 2026
Paid on
PMMF Oct 29, 2026
VUSB Oct 5, 2026
Frequency
PMMF Weekly
VUSB Monthly

Distribution history

Per share, 2026, same scale for both

PMMFWeekly · 35 paymentsAll PMMF payments⁠
One bar per payment. 35 payments in 2026 YTD. Feb 2, 2026 $0.30; Mar 2, 2026 $0.29; Apr 1, 2026 $0.28; Apr 8, 2026 $0.06; Apr 15, 2026 $0.07; Apr 22, 2026 $0.07; Apr 29, 2026 $0.07; May 6, 2026 $0.07; May 13, 2026 $0.07; May 20, 2026 $0.07; May 27, 2026 $0.07; Jun 1, 2026 $0.07; Jun 3, 2026 $0.07; Jun 10, 2026 $0.07; Jun 17, 2026 $0.07; Jun 24, 2026 $0.07; Jul 1, 2026 $0.07; Jul 8, 2026 $0.07; Jul 15, 2026 $0.07; Jul 22, 2026 $0.07; Jul 29, 2026 $0.07; Aug 3, 2026 $0.07; Aug 5, 2026 $0.07; Aug 12, 2026 $0.07; Aug 19, 2026 $0.07; Aug 26, 2026 $0.07; Sep 2, 2026 $0.07; Sep 9, 2026 $0.07; Sep 16, 2026 $0.07; Sep 23, 2026 $0.07; Sep 30, 2026 $0.08; Oct 7, 2026 $0.08; Oct 14, 2026 $0.07; Oct 21, 2026 $0.08; Oct 28, 2026 $0.07. Use the arrow keys to read each point.$0$0.252026YTD
VUSBMonthly · 9 paymentsAll VUSB payments⁠
One bar per payment. 9 payments in 2026 YTD. Feb 2, 2026 $0.18; Mar 2, 2026 $0.17; Apr 1, 2026 $0.18; May 1, 2026 $0.18; Jun 1, 2026 $0.17; Jul 1, 2026 $0.18; Aug 3, 2026 $0.17; Sep 1, 2026 $0.17; Oct 1, 2026 $0.18. Use the arrow keys to read each point.$0$0.252026YTD

PMMF vs VUSB Risk

Fall from peak · 5 years

This chart needs five years of history for both funds.

Risk facts

VolatilityStd dev, 3 years
PMMF 0.2%since Mar 2025VUSB 0.8%
Return per unit of riskSharpe ratio, 3 years
PMMF −0.63since Mar 2025VUSB 0.86
Worst fallMax drawdown, 5 years
PMMF −0.1%since Feb 2025VUSB −1.7%
Market sensitivityBeta, 5 years
PMMF −0.01VUSB 0.10

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