MIABX — MFS Inflation-Adjusted Bond Fund
Data updated: 2026-06-24
MIABX — MFS Inflation-Adjusted Bond Fund data: holdings, portfolio allocation, expenses, performance, cashflows, risk and SEC filings. Intermediate Treasury / Sovereign Bond · $1.51B AUM · 1.40% expense ratio · 2.4% 1-yr return. From SEC regulatory filings.
MIABX Fund Overview
MIABX — MFS Inflation-Adjusted Bond Fund is a US mutual fund managed by Mfs Series Trust IX, categorised as Intermediate Treasury / Sovereign 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: Intermediate Treasury / Sovereign Bond
- Assets under management: $1.51B
- 1-year return: 2.4%
- Ticker: MIABX
- SEC CIK: 0000063075
- SEC series ID: S000002493
- Share class ID: C000006726
MIABX Holdings
Top 10 holdings of MFS Inflation-Adjusted Bond Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.
| Holding | % of net assets |
|---|---|
| United States Treasury | 11.36% |
| United States Treasury | 9.53% |
| United States Treasury | 7.75% |
| United States Treasury | 7.58% |
| United States Treasury | 6.50% |
| United States Treasury | 5.48% |
| United States Treasury | 5.00% |
| United States Treasury | 4.78% |
| United States Treasury | 4.60% |
| United States Treasury | 4.14% |
MIABX Portfolio Allocation
Asset-class allocation of MFS Inflation-Adjusted Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Asset class | Allocation |
|---|---|
| Fixed Income | 89.7% |
| Securitized | 9.3% |
| Equity | 0.8% |
MIABX Performance
Total returns for MIABX (as of 2026-08-01), from SEC filings.
| Period | Total return |
|---|---|
| YTD | 1.0% |
| 1 year | 2.4% |
| 3 years (annualised) | 1.7% |
| 5 years (annualised) | -0.2% |
MIABX Risk Information
Risk metrics for MIABX, derived from monthly returns in SEC filings.
- 1-year volatility (annualised): 3.3%
MIABX Costs and Fees
MIABX costs about $140 per $10,000 invested per year in fund expenses.
- Net expense ratio: 1.40%
- Gross expense ratio: 1.58%
- Portfolio turnover: 38%
- Brokerage commissions: 0.35 bps of average net assets (SEC N-CEN)
MIABX Cashflows
Over the 12 months to 2026-04, MFS Inflation-Adjusted Bond Fund had net inflows of $75.75M, from monthly SEC N-PORT filings.
| Month | Net flow |
|---|---|
| 2026-04 | −$4.00M |
| 2026-03 | −$33.71M |
| 2026-02 | −$2.67M |
| 2026-01 | −$2.45M |
| 2025-12 | $25.22M |
| 2025-11 | −$23.16M |
MIABX Debt Constituents
Largest debt holdings of MFS Inflation-Adjusted Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Debt holding | % of net assets |
|---|---|
| United States Treasury | 11.36% |
| United States Treasury | 9.53% |
| United States Treasury | 7.75% |
| United States Treasury | 7.58% |
| United States Treasury | 6.50% |
| United States Treasury | 5.48% |
| United States Treasury | 5.00% |
| United States Treasury | 4.78% |
| United States Treasury | 4.60% |
| United States Treasury | 4.14% |
MIABX Prospectus and SEC Filings
Official MFS Inflation-Adjusted Bond Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.
Related Funds
Other Intermediate Treasury / Sovereign 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.