MFS Mid Cap Growth Fund
Actively managed U.S. stock fund
The funds investment objective is to seek capital appreciation.
The fund invests at least 80% of assets in equity securities of medium-capitalization growth companies, selected through bottom-up fundamental analysis of individual issuers. The fund may also hold foreign securities and can concentrate a significant portion of assets in a single industry or sector. Because the fund's returns depend on the manager's selection of growth companies rather than tracking a defined index, performance will diverge from any particular benchmark.
What you own
| Company | Weight | Value | Shares | Reported price |
|---|---|---|---|---|
4.26% | $587.31M | 375.0K | $1,566.21 | |
3.95% | $544.46M | 2.1M | $258.25 | |
3.34% | $459.85M | 646.1K | $711.73 | |
2.72% | $375.20M | 1.7M | $224.16 | |
2.62% | $361.54M | 2.1M | $168.41 | |
NTRANatera, Inc. | 2.18% | $300.56M | 1.3M | $223.37 |
2.12% | $292.23M | 1.4M | $205.18 | |
Masimo Corp. | 2.12% | $291.92M | 1.6M | $178.45 |
Ascendis Pharma A/S | 2.07% | $285.48M | 1.3M | $224.11 |
1.95% | $268.25M | 828.4K | $323.83 |
Reported price is the fund's own reported value divided by its own reported shares at 2026-05-31 — not a live quote, and not what the fund paid.
All 111 holdings, with the share counts as filed, open with a free account.
What the fund is made of
Percentages are of fund net assets. Rounding, liabilities and short positions can make totals differ from 100%.
| Stocks | 99.06% |
| Cash & short-term | 2.00% |
Derivatives are shown at market value, not notional exposure.
By sector
- Industrials
- 22.3%
- Information Technology
- 17.3%
- Health Care
- 12.8%
- International
- 11.4%
- 10 other sectors
- 36.2%
- Industrials
- 22.3%
- Information Technology
- 17.3%
- Health Care
- 12.8%
- International
- 11.4%
- Consumer Discretionary
- 11.0%
- Communication Services
- 8.4%
- Financials
- 4.8%
- Energy
- 4.7%
- Cash
- 2.0%
- Utilities
- 1.8%
- Materials
- 1.8%
- Consumer Staples
- 0.8%
- Other
- 0.5%
- Real Estate
- 0.5%
How it has done
OTCAX share class · total returns with dividends reinvested
Volatility over the last 12 months: 14.44%. Past returns are a record, not a forecast.
May 2026 has been filed since the trailing figures were struck, so it is not in the table above or the curve — every figure here shares one cut-off, which is what makes them comparable with other funds.
The 9 share classes hold the same portfolio
| Share class | Expense ratio | 1 year | 3 years | 5 years | Worst fall |
|---|---|---|---|---|---|
| 1.02% | +9.15% | +36.55% | +14.32% | -11.67% | |
| 0.77% | +9.42% | +37.57% | +15.83% | -11.58% | |
| 1.77% | +8.36% | +33.55% | +10.20% | -11.88% | |
| 1.77% | +8.34% | +33.50% | +10.13% | -11.90% | |
| 0.77% | +9.44% | +37.64% | +15.88% | -11.59% | |
| 1.77% | +8.36% | +33.52% | +10.13% | -11.88% | |
| 1.27% | +8.87% | +35.50% | +13.00% | -11.76% | |
| 1.02% | +9.16% | +36.53% | +14.33% | -11.68% | |
| 0.65% | +9.58% | +38.12% | +16.56% | -11.58% |
These classes hold the same portfolio, so the 6.43pp spread over 5 years is the cost difference between them — roughly 1.29pp a year — not a difference in what they own.
Fees & fund details
MFS Mid Cap Growth Fund is an actively managed U.S. equity fund. 43% of OTCAX’s stock holdings are in companies whose revenue grew in the top quartile of U.S. companies over the last five fiscal years (covering 82% of the fund’s equity).
- Asset class
- Equity
- Region
- United States
- Management
- Actively managed
- Fund type
- Open-end fund
- Expense ratio, by class
- 0.65% – 1.77%· OTCAX 1.02%
- Portfolio turnover
- 54.00% a year · as of 2025 Q4
Net is what a holder pays after the adviser's contractual waiver; gross is before it. A waiver can expire.
Turnover is how much of the portfolio was replaced in a year.
Classified from what the fund holds, not from its name · 2026 Q2. The summary is a paraphrase of the prospectus; the objective is verbatim.
What changed this quarter
Positions that entered or left the fund since its previous filing. Positions that were only resized are not listed.
18 new· the largest 8
12 exited· the largest 8
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