BBGSX vs. MIDLX

Last updated Jun 9, 2026

BBGSX (Bridge Builder Small/Mid Cap Growth Fund) and MIDLX (MFS International New Discovery Fund Class R6) are both mutual funds - BBGSX is a Mid Cap Growth Equities fund managed by Bridge Builder, while MIDLX is a Foreign Small & Mid Cap Equities fund tracking the MSCI All Country World ex-US Small Mid Cap Index. Over the past 10 years, BBGSX returned 10.27%/yr vs 6.41%/yr for MIDLX. A 0.66 correlation means they provide meaningful diversification when combined. BBGSX charges 0.38%/yr vs 0.91%/yr for MIDLX.

Performance

BBGSX vs. MIDLX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Bridge Builder Small/Mid Cap Growth Fund (BBGSX) and MFS International New Discovery Fund Class R6 (MIDLX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BBGSX achieves a 5.95% return, which is significantly higher than MIDLX's 3.83% return. Over the past 10 years, BBGSX has outperformed MIDLX with an annualized return of 10.27%, while MIDLX has yielded a comparatively lower 6.41% annualized return.

BBGSX

• 1D: -3.52%
• 1M: 0.41%
• YTD: 5.95%
• 6M: -2.82%
• 1Y: 7.20%
• 3Y*: 10.43%
• 5Y*: 2.57%
• 10Y*: 10.27%

MIDLX

• 1D: -2.35%
• 1M: -3.37%
• YTD: 3.83%
• 6M: 4.94%
• 1Y: 7.50%
• 3Y*: 9.96%
• 5Y*: 2.83%
• 10Y*: 6.41%

*Multi-year figures are annualized to reflect compound growth (CAGR)

BBGSX vs. MIDLX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BBGSX Bridge Builder Small/Mid Cap Growth Fund	5.95%	0.99%	14.47%	20.98%	-29.84%	16.57%	34.41%	29.01%	-2.18%	21.47%
MIDLX MFS International New Discovery Fund Class R6	3.83%	17.03%	3.33%	13.21%	-18.52%	5.17%	10.15%	24.97%	-10.29%	30.65%

Correlation

The correlation between BBGSX and MIDLX is 0.62, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.62
Correlation (3Y) Calculated over the trailing 3-year period	0.61
Correlation (5Y) Calculated over the trailing 5-year period	0.67
Correlation (10Y) Calculated over the trailing 10-year period	0.66
Correlation (All Time) Calculated using the full available price history since Jan 5, 2016	0.66

The correlation between BBGSX and MIDLX has been stable across timeframes, ranging from 0.61 to 0.67 - a consistent structural relationship.

Return for Risk

BBGSX vs. MIDLX — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

BBGSX

BBGSX Risk / Return Rank: 7
BBGSX Sharpe Ratio Rank: 7
BBGSX Sortino Ratio Rank: 7
BBGSX Omega Ratio Rank: 7
BBGSX Calmar Ratio Rank: 6
BBGSX Martin Ratio Rank: 7

MIDLX

MIDLX Risk / Return Rank: 9
MIDLX Sharpe Ratio Rank: 9
MIDLX Sortino Ratio Rank: 9
MIDLX Omega Ratio Rank: 9
MIDLX Calmar Ratio Rank: 8
MIDLX Martin Ratio Rank: 9

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

BBGSX vs. MIDLX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Bridge Builder Small/Mid Cap Growth Fund (BBGSX) and MFS International New Discovery Fund Class R6 (MIDLX). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.

	BBGSX	MIDLX	Difference
Sharpe ratio: Return per unit of total volatility	0.46	0.64	-0.18
Sortino ratio: Return per unit of downside risk	0.76	0.98	-0.22
Omega ratio: Gain probability vs. loss probability	1.09	1.12	-0.03
Calmar ratio: Return relative to maximum drawdown	0.50	0.64	-0.14
Martin ratio: Return relative to average drawdown	1.49	2.20	-0.71
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

BBGSX vs. MIDLX - Sharpe Ratio Comparison

The current BBGSX Sharpe Ratio is 0.46, which is comparable to the MIDLX Sharpe Ratio of 0.64. The chart below compares the historical Sharpe Ratios of BBGSX and MIDLX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	BBGSX	MIDLX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.46	0.64	-0.18
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.12	0.21	-0.10
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.49	0.46	+0.03
Sharpe Ratio (All Time) Calculated using the full available price history	0.51	0.57	-0.07

Drawdowns

BBGSX vs. MIDLX - Drawdown Comparison

The maximum BBGSX drawdown since its inception was -37.95%, which is greater than MIDLX's maximum drawdown of -34.70%. Use the drawdown chart below to compare losses from any high point for BBGSX and MIDLX.

Drawdown Indicators

	BBGSX	MIDLX	Difference
Max Drawdown Largest peak-to-trough decline	-37.95%	-34.70%	-3.25%
Max Drawdown (1Y) Largest decline over 1 year	-16.72%	-11.75%	-4.97%
Max Drawdown (3Y) Largest decline over 3 years	-26.11%	-13.15%	-12.96%
Max Drawdown (5Y) Largest decline over 5 years	-37.95%	-33.58%	-4.37%
Max Drawdown (10Y) Largest decline over 10 years	-37.95%	-34.70%	-3.25%
Current Drawdown Current decline from peak	-4.43%	-4.51%	+0.08%
Average Drawdown Average peak-to-trough decline	-9.56%	-6.92%	-2.64%
Ulcer Index Depth and duration of drawdowns from previous peaks	5.50%	3.42%	+2.08%

Volatility

BBGSX vs. MIDLX - Volatility Comparison

Bridge Builder Small/Mid Cap Growth Fund (BBGSX) has a higher volatility of 5.81% compared to MFS International New Discovery Fund Class R6 (MIDLX) at 3.57%. This indicates that BBGSX's price experiences larger fluctuations and is considered to be riskier than MIDLX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BBGSX	MIDLX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.81%	3.57%	+2.24%
Volatility (6M) Calculated over the trailing 6-month period	14.48%	9.79%	+4.69%
Volatility (1Y) Calculated over the trailing 1-year period	18.05%	11.73%	+6.32%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.74%	13.24%	+8.50%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.99%	14.02%	+6.97%

BBGSX vs. MIDLX - Expense Ratio Comparison

BBGSX has a 0.38% expense ratio, which is lower than MIDLX's 0.91% expense ratio.

Dividends

BBGSX vs. MIDLX - Dividend Comparison

BBGSX has not paid dividends to shareholders, while MIDLX's dividend yield for the trailing twelve months is around 3.25%.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BBGSX Bridge Builder Small/Mid Cap Growth Fund	0.00%	0.00%	0.58%	0.32%	0.19%	18.00%	12.59%	4.07%	6.12%	1.09%	0.36%	0.00%
MIDLX MFS International New Discovery Fund Class R6	3.25%	3.37%	10.08%	4.21%	5.85%	5.19%	4.03%	4.36%	6.82%	1.63%	1.09%	1.25%

Frequently Asked Questions

Can I hold both BBGSX and MIDLX in my portfolio?

BBGSX and MIDLX have a correlation of 0.62, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, BBGSX or MIDLX?

BBGSX has higher volatility (5.81%) compared to MIDLX (3.57%). In terms of maximum drawdown, BBGSX dropped -37.95% vs MIDLX's -34.70%.

Which has better risk-adjusted returns?

MIDLX currently has the higher Sharpe Ratio (0.64 vs 0.46), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.