TRIEX vs. MIEKX

Last updated Jun 3, 2026

TRIEX (Nuveen International Equity Index Fund Retirement Class) and MIEKX (MFS International Equity Fund Class R6) are both International Equity funds. TRIEX is passively managed, while MIEKX is actively managed. Over the past 3 years, TRIEX returned 16.65%/yr vs 11.91%/yr for MIEKX. Their correlation of 0.94 suggests significant overlap in exposure. TRIEX charges 0.30%/yr vs 0.73%/yr for MIEKX.

Performance

TRIEX vs. MIEKX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Nuveen International Equity Index Fund Retirement Class (TRIEX) and MFS International Equity Fund Class R6 (MIEKX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, TRIEX achieves a 9.05% return, which is significantly higher than MIEKX's 3.06% return.

TRIEX

• 1D: -0.26%
• 1M: 2.56%
• YTD: 9.05%
• 6M: 11.95%
• 1Y: 20.55%
• 3Y*: 16.65%
• 5Y*: 8.37%
• 10Y*: 9.08%

MIEKX

• 1D: -0.67%
• 1M: 2.55%
• YTD: 3.06%
• 6M: 5.76%
• 1Y: 9.26%
• 3Y*: 11.91%
• 5Y*: —
• 10Y*: —

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

TRIEX vs. MIEKX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023
TRIEX Nuveen International Equity Index Fund Retirement Class	9.05%	31.24%	3.41%	6.12%
MIEKX MFS International Equity Fund Class R6	3.06%	23.12%	4.02%	5.55%

Correlation

The correlation between TRIEX and MIEKX is 0.91, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.91
Correlation (3Y) Calculated over the trailing 3-year period	0.93
Correlation (All Time) Calculated using the full available price history since May 18, 2023	0.94

The correlation between TRIEX and MIEKX has been stable across timeframes, ranging from 0.91 to 0.94 - a consistent structural relationship.

Return for Risk

TRIEX vs. MIEKX — Risk / Return Rank

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

TRIEX

TRIEX Risk / Return Rank: 27
TRIEX Sharpe Ratio Rank: 26
TRIEX Sortino Ratio Rank: 25
TRIEX Omega Ratio Rank: 25
TRIEX Calmar Ratio Rank: 29
TRIEX Martin Ratio Rank: 33

MIEKX

MIEKX Risk / Return Rank: 10
MIEKX Sharpe Ratio Rank: 10
MIEKX Sortino Ratio Rank: 10
MIEKX Omega Ratio Rank: 10
MIEKX Calmar Ratio Rank: 9
MIEKX Martin Ratio Rank: 10

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.

TRIEX vs. MIEKX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Nuveen International Equity Index Fund Retirement Class (TRIEX) and MFS International Equity Fund Class R6 (MIEKX). 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.

	TRIEX	MIEKX	Difference
Sharpe ratio Return per unit of total volatility	1.46	0.80	+0.66
Sortino ratio Return per unit of downside risk	2.09	1.20	+0.89
Omega ratio Gain probability vs. loss probability	1.26	1.15	+0.11
Calmar ratio Return relative to maximum drawdown	2.01	0.92	+1.08
Martin ratio Return relative to average drawdown	7.51	3.26	+4.25
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

TRIEX vs. MIEKX - Sharpe Ratio Comparison

The current TRIEX Sharpe Ratio is 1.46, which is higher than the MIEKX Sharpe Ratio of 0.80. The chart below compares the historical Sharpe Ratios of TRIEX and MIEKX, 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

	TRIEX	MIEKX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.46	0.80	+0.66
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.52	—	—
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.55	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.41	0.88	-0.47

Drawdowns

TRIEX vs. MIEKX - Drawdown Comparison

The maximum TRIEX drawdown since its inception was -60.73%, which is greater than MIEKX's maximum drawdown of -13.42%. Use the drawdown chart below to compare losses from any high point for TRIEX and MIEKX.

Drawdown Indicators

	TRIEX	MIEKX	Difference
Max Drawdown Largest peak-to-trough decline	-60.73%	-13.42%	-47.31%
Max Drawdown (1Y) Largest decline over 1 year	-11.37%	-11.30%	-0.07%
Max Drawdown (3Y) Largest decline over 3 years	-13.55%	-13.42%	-0.13%
Max Drawdown (5Y) Largest decline over 5 years	-29.44%	—	—
Max Drawdown (10Y) Largest decline over 10 years	-33.96%	—	—
Current Drawdown Current decline from peak	-0.89%	-1.67%	+0.78%
Average Drawdown Average peak-to-trough decline	-11.44%	-2.84%	-8.60%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.04%	3.20%	-0.16%

Volatility

TRIEX vs. MIEKX - Volatility Comparison

Nuveen International Equity Index Fund Retirement Class (TRIEX) has a higher volatility of 4.73% compared to MFS International Equity Fund Class R6 (MIEKX) at 3.50%. This indicates that TRIEX's price experiences larger fluctuations and is considered to be riskier than MIEKX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TRIEX	MIEKX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.73%	3.50%	+1.23%
Volatility (6M) Calculated over the trailing 6-month period	12.33%	10.22%	+2.11%
Volatility (1Y) Calculated over the trailing 1-year period	15.17%	13.19%	+1.98%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.10%	13.24%	+2.86%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	16.65%	13.24%	+3.41%

TRIEX vs. MIEKX - Expense Ratio Comparison

TRIEX has a 0.30% expense ratio, which is lower than MIEKX's 0.73% expense ratio.

Dividends

TRIEX vs. MIEKX - Dividend Comparison

TRIEX's dividend yield for the trailing twelve months is around 3.27%, more than MIEKX's 2.52% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MIEKX MFS International Equity Fund Class R6	2.52%	2.60%	1.41%	1.67%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
TRIEX Nuveen International Equity Index Fund Retirement Class	3.27%	3.57%	2.84%	2.83%	2.49%	2.69%	1.70%	2.78%	3.05%	2.51%	2.65%	2.72%

Frequently Asked Questions

Can I hold both TRIEX and MIEKX in my portfolio?

With a correlation of 0.91, TRIEX and MIEKX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, TRIEX or MIEKX?

TRIEX has higher volatility (4.73%) compared to MIEKX (3.50%). In terms of maximum drawdown, TRIEX dropped -60.73% vs MIEKX's -13.42%.

Which has better risk-adjusted returns?

TRIEX currently has the higher Sharpe Ratio (1.46 vs 0.80), 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.