MRBFX — MFS Total Return Bond Fund
Data updated: 2026-07-13
MRBFX — MFS Total Return Bond Fund data: holdings, portfolio allocation, expenses, performance, cashflows, risk and SEC filings. Long Total / Aggregate Bond · $8.26B AUM · 0.60% expense ratio · 4.4% 1-yr return. From SEC regulatory filings.
MRBFX Fund Overview
MRBFX — MFS Total Return Bond Fund is a US mutual fund managed by Mfs Series Trust IX, categorised as Long Total / Aggregate Bond. ABC INVEST provides holdings, performance, costs, cashflows, risk data, prospectus documents and SEC filings, sourced from SEC filings.
- Type: US mutual fund
- Manager: Mfs Series Trust IX
- Category: Long Total / Aggregate Bond
- Assets under management: $8.26B
- 1-year return: 4.4%
- Ticker: MRBFX
- SEC CIK: 0000063075
- SEC series ID: S000002497
- Share class ID: C000006760
MRBFX Holdings
Top 10 holdings of MFS Total Return Bond Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.
| Holding | % of net assets |
|---|---|
| United States of America | 3.28% |
| United States of America | 2.11% |
| United States of America | 2.04% |
| United States of America | 1.96% |
| MFS Institutional Money Market Portfolio | 1.53% |
| United States of America | 1.23% |
| United States of America | 1.15% |
| United States of America | 1.13% |
| United States of America | 1.12% |
| FHLMC Pool | 1.08% |
MRBFX Portfolio Allocation
Asset-class allocation of MFS Total Return Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Asset class | Allocation |
|---|---|
| Fixed Income | 61.7% |
| Securitized | 37.3% |
| Cash & Equivalents | 1.5% |
MRBFX Performance
Total returns for MRBFX (as of 2026-08-01), from SEC filings.
| Period | Total return |
|---|---|
| YTD | 0.2% |
| 1 year | 4.4% |
| 3 years (annualised) | 4.2% |
| 5 years (annualised) | 0.5% |
MRBFX Risk Information
Risk metrics for MRBFX, derived from monthly returns in SEC filings.
- 1-year volatility (annualised): 3.3%
MRBFX Costs and Fees
MRBFX costs about $60 per $10,000 invested per year in fund expenses.
- Net expense ratio: 0.60%
- Gross expense ratio: 0.77%
- Portfolio turnover: 75%
- Brokerage commissions: 0.27 bps of average net assets (SEC N-CEN)
MRBFX Cashflows
Over the 12 months to 2026-04, MFS Total Return Bond Fund had net inflows of $159.28M, from monthly SEC N-PORT filings.
| Month | Net flow |
|---|---|
| 2026-04 | −$20.80M |
| 2026-03 | −$42.84M |
| 2026-02 | $48.79M |
| 2026-01 | $19.49M |
| 2025-12 | $4.45M |
| 2025-11 | $9.74M |
MRBFX Debt Constituents
Largest debt holdings of MFS Total Return Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Debt holding | % of net assets |
|---|---|
| United States of America | 3.28% |
| United States of America | 2.11% |
| United States of America | 2.04% |
| United States of America | 1.96% |
| United States of America | 1.23% |
| United States of America | 1.15% |
| United States of America | 1.13% |
| United States of America | 1.12% |
| United States of America | 1.04% |
| United States of America | 0.87% |
MRBFX Prospectus and SEC Filings
Official MFS Total Return Bond Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.
Related Funds
Other Long Total / Aggregate 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.