MNDBX Performance — MFS New Discovery Fund, Class B
Data updated: 2026-07-27
MNDBX returned +10.46% year to date and +26.43% over one year to May 2026. Annualised returns are +12.91% over 3 years and −0.23% over 5 years. The fund trailed its US Small Growth category average: $100 invested three years ago grew to $144, against $157 for the category, and to $126 over one year, against $130. Volatility over the past three years was 17.12% a year. In the 12 months to May 2026 the fund lost a net $363.8M, and assets reached $2.14B.
MNDBX Growth of $100
What $100 invested in MFS New Discovery Fund grew to, compounded from monthly returns reported on SEC Form N-PORT, against the US Small Growth category average over the same months.
| Period | MNDBX | Category average |
|---|---|---|
| 1 year (Jun 2025 – May 2026) | $126 | $130 |
| 3 years (Jun 2023 – May 2026) | $144 | $157 |
| 5 years (Jun 2021 – May 2026) | $99 | $124 |
| Since data start (Sep 2019 – May 2026) | $161 | $195 |
MNDBX Trailing Returns
Total returns to May 2026, from SEC N-PORT.
| Period | Total return |
|---|---|
| YTD | +10.46% |
| 1 year | +26.43% |
| 3 years (annualised) | +12.91% |
| 5 years (annualised) | −0.23% |
MNDBX Annual Returns
Calendar-year total returns of MFS New Discovery Fund, compounded from monthly SEC N-PORT returns. Partial years show the months covered.
| Year | Total return |
|---|---|
| 2026 (Jan–May) | +10.46% |
| 2025 | +11.53% |
| 2024 | +5.31% |
| 2023 | +13.17% |
| 2022 | −30.38% |
| 2021 | +0.48% |
| 2020 | +43.56% |
| 2019 (Sep–Dec) | +9.27% |
MNDBX Monthly Returns
Monthly total returns as reported on SEC Form N-PORT.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | +4.0% | +0.1% | −6.1% | +9.9% | +2.7% | — | — | — | — | — | — | — |
| 2025 | +5.0% | −5.7% | −6.6% | +0.1% | +5.2% | +6.0% | +0.1% | +3.0% | +0.8% | +2.6% | +2.4% | −1.1% |
| 2024 | −1.4% | +5.9% | +2.0% | −6.5% | +2.6% | 0.0% | +4.5% | −0.4% | −0.5% | −0.2% | +8.0% | −7.6% |
| 2023 | +10.6% | −2.4% | −1.1% | −0.4% | −4.0% | +8.0% | +3.9% | −4.3% | −6.1% | −6.5% | +7.7% | +9.2% |
| 2022 | −13.9% | −0.8% | −1.7% | −10.6% | −1.0% | −8.3% | +9.7% | −2.9% | −9.5% | +7.8% | +3.9% | −5.2% |
| 2021 | +1.6% | +1.3% | −2.1% | +4.8% | −1.6% | +4.1% | −0.4% | +3.5% | −4.5% | +3.9% | −7.5% | −1.7% |
| 2020 | −0.1% | −6.4% | −17.1% | +17.1% | +10.8% | +3.5% | +5.5% | +5.4% | −0.2% | +0.6% | +12.3% | +9.9% |
| 2019 | — | — | — | — | — | — | — | — | −1.2% | +1.1% | +6.1% | +3.1% |
MNDBX Risk
Risk measures from monthly returns over Jun 2023 – May 2026.
- 3-year volatility (annualised): 17.12%
- 3-year Sharpe ratio: 0.49 (vs 4.5% risk-free rate)
- Best month: +9.94% (Apr 2026)
- Worst month: −7.65% (Dec 2024)
MNDBX Fund Flows
Monthly money in and out of MFS New Discovery Fund, from SEC Form N-PORT.
- 12-month net flow: −$363.8M
- 12-month gross sales (incl. reinvestments): $216.0M
- Sales ÷ redemptions: 0.37×
| Month | Sales | Redemptions | Net flow |
|---|---|---|---|
| May 2026 | $8.5M | $43.4M | −$34.9M |
| Apr 2026 | $15.5M | $40.9M | −$25.4M |
| Mar 2026 | $17.5M | $37.0M | −$19.5M |
| Feb 2026 | $18.7M | $31.9M | −$13.2M |
| Jan 2026 | $15.2M | $47.7M | −$32.5M |
| Dec 2025 | $13.5M | $52.6M | −$39.1M |
| Nov 2025 | $13.3M | $43.3M | −$30.0M |
| Oct 2025 | $51.9M | $72.5M | −$20.6M |
| Sep 2025 | $14.2M | $60.5M | −$46.3M |
| Aug 2025 | $21.2M | $52.6M | −$31.4M |
| Jul 2025 | $14.5M | $57.7M | −$43.3M |
| Jun 2025 | $12.0M | $39.7M | −$27.7M |
MNDBX Assets Under Management
Net assets of MFS New Discovery Fund by report date, from SEC N-PORT filings.
| Report date | Net assets |
|---|---|
| 2026-05-31 | $2.14B |
| 2026-02-28 | $2.09B |
| 2025-11-30 | $2.11B |
| 2025-08-31 | $2.08B |
| 2025-05-31 | $2.00B |
| 2025-02-28 | $2.09B |
| 2024-11-30 | $2.41B |
| 2024-08-31 | $2.34B |
| 2024-05-31 | $2.32B |
| 2024-02-29 | $2.46B |
| 2023-11-30 | $2.24B |
| 2023-08-31 | $2.38B |
For information only. Not investment advice: figures are as reported in SEC filings and may contain errors or be out of date. Past performance does not guarantee future results.