SBISX — MFS Inflation-Adjusted Bond Portfolio
Data updated: 2026-08-24
SBISX — MFS Inflation-Adjusted Bond Portfolio. Long Total / Aggregate Bond · $148.19M AUM · 0.85% expense ratio. Holdings, fees, performance and SEC filings.
SBISX Fund Overview
SBISX — MFS Inflation-Adjusted Bond Portfolio is a US mutual fund managed by Mfs Variable Insurance Trust III, 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 Variable Insurance Trust III
- Category: Long Total / Aggregate Bond
- Assets under management: $148.19M
- 1-year return: 0.7%
- Ticker: SBISX
- SEC CIK: 0001065698
- SEC series ID: S000023378
- Share class ID: C000068455
SBISX Investment Objective and Strategy
MFS Inflation-Adjusted Bond Portfolio describes its objective and strategy as follows, from its latest prospectus filed with the SEC by Mfs Variable Insurance Trust III.
Investment objective
The funds investment objective is to seek total return that exceeds the rate of inflation over the long-term, with an emphasis on current income, but also considering capital appreciation.
Principal investment strategy
MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the funds net assets in inflation-adjusted debt instruments and other instruments with similar economic characteristics. Inflation-adjusted debt instruments are debt instruments whose principal and/or interest payments are adjusted for realized inflation. MFS generally focuses the funds investments in inflation-adjusted debt instruments issued by U.S. and foreign governments. MFS may also invest the funds assets in inflation-adjusted debt instruments of other issuers, other instruments with similar economic characteristics to these instruments, including derivatives, and non-inflation-adjusted debt instruments. MFS primarily invests the funds assets in investment grade quality debt instruments, but may also invest the funds assets in below investment grade quality debt instruments.
MFS invests the funds assets in U.S. and foreign securities. MFS normally invests the fund's assets across different countries and regions, but MFS may invest a significant percentage of the fund's assets in issuers in a single country or region. The fund is a non-diversified fund. This means that MFS may invest a significant percentage of the funds assets in a single issuer or a small number of issuers. While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate or currency exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, and swaps.
MFS uses an active investment approach in managing the fund that combines top-down considerations and bottom-up fundamental investment analysis to make decisions about sector allocations, duration and yield curve positioning, and security selection. In addition, market technicals (e.g., bond supply and demand dynamics) are typically considered in determining sector allocations and specific security selection. Quantitative screening tools may also be considered in determining the funds portfolio positioning. For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.
SBISX Holdings
Top 10 holdings of MFS Inflation-Adjusted Bond Portfolio by percentage of net assets, from the fund's latest SEC N-PORT filing.
| Holding | % of net assets |
|---|---|
| United Kingdom I/l Gilt | 20.46% |
| Buoni Poliennali Del Tes | 11.19% |
| United States Treasury | 10.88% |
| United States Treasury | 8.24% |
| United States Treasury | 6.74% |
| United States Treasury | 5.93% |
| United States Treasury | 5.39% |
| Spain I/l Bond | 3.83% |
| France (govt Of) | 3.70% |
| United States Treasury | 3.30% |
SBISX Portfolio Allocation
Asset-class allocation of MFS Inflation-Adjusted Bond Portfolio by percentage of net assets, from the latest SEC N-PORT filing.
| Asset class | Allocation |
|---|---|
| Fixed Income | 95.0% |
| Securitized | 4.7% |
| Equity | 0.1% |
SBISX Performance
Total returns for SBISX (as of 2026-10-01), from SEC filings.
| Period | Total return |
|---|---|
| YTD | 0.1% |
| 1 year | 0.7% |
| 3 years (annualised) | 2.0% |
| 5 years (annualised) | -3.1% |
SBISX Risk Information
Risk metrics for SBISX, derived from monthly returns in SEC filings.
- 1-year volatility (annualised): 5.3%
SBISX Costs and Fees
SBISX costs about $85 per $10,000 invested per year in fund expenses.
- Net expense ratio: 0.85%
- Gross expense ratio: 0.86%
- Portfolio turnover: 43%
- Brokerage commissions: 0.57 bps of average net assets (SEC N-CEN)
SBISX Cashflows
Over the 12 months to 2026-06, MFS Inflation-Adjusted Bond Portfolio had net outflows of $5.46M, from monthly SEC N-PORT filings.
| Month | Net flow |
|---|---|
| 2026-06 | $2.17M |
| 2026-05 | −$435.74K |
| 2026-04 | −$1.16M |
| 2026-03 | −$3.14M |
| 2026-02 | −$2.06M |
| 2026-01 | −$1.51M |
SBISX Debt Constituents
Largest debt holdings of MFS Inflation-Adjusted Bond Portfolio by percentage of net assets, from the latest SEC N-PORT filing.
| Debt holding | % of net assets |
|---|---|
| United Kingdom I/l Gilt | 20.46% |
| Buoni Poliennali Del Tes | 11.19% |
| United States Treasury | 10.88% |
| United States Treasury | 8.24% |
| United States Treasury | 6.74% |
| United States Treasury | 5.93% |
| United States Treasury | 5.39% |
| Spain I/l Bond | 3.83% |
| France (govt Of) | 3.70% |
| United States Treasury | 3.30% |
SBISX Prospectus and SEC Filings
Official MFS Inflation-Adjusted Bond Portfolio filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.
- Prospectus (485BPOS) — filed 2026-04-29
- Prospectus (485BPOS) — filed 2025-04-29
- Prospectus (485BPOS) — filed 2024-04-26
- Portfolio holdings (N-PORT) — filed 2026-08-24
- Portfolio holdings (N-PORT) — filed 2026-05-26
- Portfolio holdings (N-PORT) — filed 2026-02-24
- Annual census (N-CEN) — filed 2026-03-13
- Annual census (N-CEN) — filed 2025-03-14
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.