OWMBX — Old Westbury Municipal Bond Fund
Data updated: 2026-09-22
OWMBX — Old Westbury Municipal Bond Fund. 0.57% expense ratio · Intermediate Municipal - National Bond. Holdings, fees, performance and SEC filings.
OWMBX Fund Overview
OWMBX — Old Westbury Municipal Bond Fund is a US mutual fund managed by Old Westbury Funds Inc., categorised as Intermediate Municipal - National Bond. ABC INVEST provides holdings, performance, costs, cashflows, risk data, prospectus documents and SEC filings, sourced from SEC filings.
- Type: US mutual fund
- Manager: Old Westbury Funds Inc.
- Category: Intermediate Municipal - National Bond
- Assets under management: $4.50B
- 1-year return: 2.3%
- Ticker: OWMBX
- SEC CIK: 0000909994
- SEC series ID: S000001861
- Share class ID: C000004838
OWMBX Investment Objective and Strategy
Old Westbury Municipal Bond Fund describes its objective and strategy as follows, from its latest prospectus filed with the SEC by Old Westbury Funds Inc..
Investment objective
The Funds goal is to seek total return (consisting of current income that is exempt from regular federal income tax and capital appreciation).
Principal investment strategy
The Fund invests primarily in a diversified portfolio of investment-grade municipal securities, which include tax-free debt securities of states, territories, and possessions of the U.S. and political subdivisions and taxing authorities of these entities, with a goal of seeking total return (consisting of current income that is exempt from regular federal income tax and capital appreciation). At least 80% of the Funds income from investments in municipal securities will be exempt from regular federal income tax. Interest from the Funds investments may be subject to the federal alternative minimum tax. The Fund invests, as a non-fundamental policy, at least 80% of its net assets, plus borrowings for investment purposes, in municipal bonds. The Fund also may invest in exchange-traded funds (ETFs).
Fixed income securities held by the Fund may be of any maturity.
OWMBX Holdings
Top 10 holdings of Old Westbury Municipal Bond Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.
| Holding | % of net assets |
|---|---|
| Money Market Obligations Trust | 2.95% |
| Denver (co), City and County of | 0.64% |
| New Jersey St Tpk Auth | 0.60% |
| Washington (wa), State of | 0.58% |
| Children's Healthcare of Atlanta, Inc. | 0.58% |
| New York N Y | 0.56% |
| Metropolitan Govt Nashville & Davidson Cnty Tenn Health & Edl Facs Brd | 0.49% |
| Washington (wa), State of | 0.49% |
| New Hampshire Health and Educational Facilities Authority (nh) | 0.49% |
| New York State Urban Development Corp. (ny) | 0.49% |
OWMBX Portfolio Allocation
Asset-class allocation of Old Westbury Municipal Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Asset class | Allocation |
|---|---|
| Fixed Income | 97.2% |
| Cash & Equivalents | 3.0% |
OWMBX Performance
Total returns for OWMBX (as of 2026-10-01), from SEC filings.
| Period | Total return |
|---|---|
| YTD | -0.65% |
| 1 year | 2.35% |
| 3 years (annualised) | 2.25% |
| 5 years (annualised) | 0.33% |
OWMBX Risk Information
Risk metrics for OWMBX, derived from monthly returns in SEC filings.
- 1-year volatility (annualised): 3.28%
OWMBX Costs and Fees
OWMBX costs about $57 per $10,000 invested per year in fund expenses.
- Net expense ratio: 0.57%
- Gross expense ratio: 0.65%
- Portfolio turnover: 52%
- Brokerage commissions: 0.00 bps of average net assets (SEC N-CEN)
OWMBX Cashflows
Over the 12 months to 2026-04, Old Westbury Municipal Bond Fund had net inflows of $301.57M, from monthly SEC N-PORT filings.
| Month | Net flow |
|---|---|
| 2026-04 | $27.47M |
| 2026-03 | $38.97M |
| 2026-02 | $48.22M |
| 2026-01 | $91.00M |
| 2025-12 | $45.26M |
| 2025-11 | −$9.17M |
OWMBX Debt Constituents
Largest debt holdings of Old Westbury Municipal Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Debt holding | % of net assets |
|---|---|
| Denver (co), City and County of | 0.64% |
| New Jersey St Tpk Auth | 0.60% |
| Washington (wa), State of | 0.58% |
| Children's Healthcare of Atlanta, Inc. | 0.58% |
| New York N Y | 0.56% |
| Metropolitan Govt Nashville & Davidson Cnty Tenn Health & Edl Facs Brd | 0.49% |
| Washington (wa), State of | 0.49% |
| New Hampshire Health and Educational Facilities Authority (nh) | 0.49% |
| New York State Urban Development Corp. (ny) | 0.49% |
| Washington (wa), State of | 0.48% |
OWMBX Prospectus and SEC Filings
Official Old Westbury Municipal Bond Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.
- Prospectus (485BPOS) — filed 2026-02-27
- Prospectus (485BPOS) — filed 2025-02-14
- Prospectus (485BPOS) — filed 2024-02-28
- Portfolio holdings (N-PORT) — filed 2026-09-22
- Portfolio holdings (N-PORT) — filed 2026-06-26
- Portfolio holdings (N-PORT) — filed 2026-03-31
- Annual census (N-CEN) — filed 2026-01-14
- Annual census (N-CEN) — filed 2025-01-13
Related Funds
Other Intermediate Municipal - National Bond funds tracked on ABC INVEST:
Data Sources
ABC INVEST compiles this page from public filings made to the U.S. Securities and Exchange Commission (SEC) through EDGAR: portfolio holdings and monthly cashflows from Form N-PORT, expenses and returns from fund prospectuses (Form 485BPOS) and the SEC DERA Risk/Return Summary data sets, annual data from Form N-CEN, and shareholder reports from Form N-CSR.