MRBIX vs. TGRNX

Last updated Jun 5, 2026

MRBIX (MFS Total Return Bond Fund) and TGRNX (TIAA-CREF Green Bond Fund) are both Intermediate Core-Plus Bond funds. Over the past 5 years, MRBIX returned 0.11%/yr vs 0.32%/yr for TGRNX. Their correlation of 0.93 suggests significant overlap in exposure. Both charge a 0.45% expense ratio.

Performance

MRBIX vs. TGRNX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Total Return Bond Fund (MRBIX) and TIAA-CREF Green Bond Fund (TGRNX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MRBIX achieves a 0.31% return, which is significantly lower than TGRNX's 0.46% return.

MRBIX

• 1D: -0.21%
• 1M: 0.13%
• YTD: 0.31%
• 6M: 0.47%
• 1Y: 4.78%
• 3Y*: 4.28%
• 5Y*: 0.11%
• 10Y*: 1.95%

TGRNX

• 1D: -0.22%
• 1M: 0.25%
• YTD: 0.46%
• 6M: 0.70%
• 1Y: 4.70%
• 3Y*: 4.57%
• 5Y*: 0.32%
• 10Y*: —

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

MRBIX vs. TGRNX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018
MRBIX MFS Total Return Bond Fund	0.31%	7.35%	1.77%	6.45%	-14.52%	-0.84%	8.83%	9.96%	1.61%
TGRNX TIAA-CREF Green Bond Fund	0.46%	6.76%	3.08%	5.73%	-13.43%	-0.60%	8.57%	9.15%	1.43%

Correlation

The correlation between MRBIX and TGRNX is 0.93, 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	0.93
Correlation (3Y) Calculated over the trailing 3-year period	0.96
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (All Time) Calculated using the full available price history since Nov 19, 2018	0.93

The correlation between MRBIX and TGRNX has been stable across timeframes, ranging from 0.93 to 0.96 - a consistent structural relationship.

Return for Risk

MRBIX vs. TGRNX — Risk / Return Rank

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

MRBIX

MRBIX Risk / Return Rank: 26
MRBIX Sharpe Ratio Rank: 25
MRBIX Sortino Ratio Rank: 28
MRBIX Omega Ratio Rank: 24
MRBIX Calmar Ratio Rank: 29
MRBIX Martin Ratio Rank: 24

TGRNX

TGRNX Risk / Return Rank: 35
TGRNX Sharpe Ratio Rank: 34
TGRNX Sortino Ratio Rank: 39
TGRNX Omega Ratio Rank: 36
TGRNX Calmar Ratio Rank: 33
TGRNX Martin Ratio Rank: 30

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.

MRBIX vs. TGRNX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Total Return Bond Fund (MRBIX) and TIAA-CREF Green Bond Fund (TGRNX). 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.

	MRBIX	TGRNX	Difference
Sharpe ratio: Return per unit of total volatility	1.42	1.66	-0.24
Sortino ratio: Return per unit of downside risk	2.15	2.57	-0.42
Omega ratio: Gain probability vs. loss probability	1.25	1.31	-0.06
Calmar ratio: Return relative to maximum drawdown	1.98	2.11	-0.13
Martin ratio: Return relative to average drawdown	5.76	6.89	-1.13
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MRBIX vs. TGRNX - Sharpe Ratio Comparison

The current MRBIX Sharpe Ratio is 1.42, which is comparable to the TGRNX Sharpe Ratio of 1.66. The chart below compares the historical Sharpe Ratios of MRBIX and TGRNX, 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

	MRBIX	TGRNX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.42	1.66	-0.24
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.02	0.07	-0.05
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.40	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.97	0.53	+0.44

Drawdowns

MRBIX vs. TGRNX - Drawdown Comparison

The maximum MRBIX drawdown since its inception was -19.25%, which is greater than TGRNX's maximum drawdown of -17.85%. Use the drawdown chart below to compare losses from any high point for MRBIX and TGRNX.

Drawdown Indicators

	MRBIX	TGRNX	Difference
Max Drawdown Largest peak-to-trough decline	-19.25%	-17.85%	-1.40%
Max Drawdown (1Y) Largest decline over 1 year	-2.77%	-2.47%	-0.30%
Max Drawdown (3Y) Largest decline over 3 years	-6.29%	-3.99%	-2.30%
Max Drawdown (5Y) Largest decline over 5 years	-19.25%	-17.85%	-1.40%
Max Drawdown (10Y) Largest decline over 10 years	-19.25%	—	—
Current Drawdown Current decline from peak	-1.50%	-0.99%	-0.51%
Average Drawdown Average peak-to-trough decline	-2.47%	-5.22%	+2.75%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.95%	0.75%	+0.20%

Volatility

MRBIX vs. TGRNX - Volatility Comparison

MFS Total Return Bond Fund (MRBIX) has a higher volatility of 1.30% compared to TIAA-CREF Green Bond Fund (TGRNX) at 1.06%. This indicates that MRBIX's price experiences larger fluctuations and is considered to be riskier than TGRNX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MRBIX	TGRNX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.30%	1.06%	+0.24%
Volatility (6M) Calculated over the trailing 6-month period	2.70%	2.31%	+0.39%
Volatility (1Y) Calculated over the trailing 1-year period	3.85%	3.15%	+0.70%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.73%	4.84%	+0.89%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.92%	4.82%	+0.10%

MRBIX vs. TGRNX - Expense Ratio Comparison

Both MRBIX and TGRNX have an expense ratio of 0.45%.

Dividends

MRBIX vs. TGRNX - Dividend Comparison

MRBIX's dividend yield for the trailing twelve months is around 4.17%, less than TGRNX's 4.30% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MRBIX MFS Total Return Bond Fund	4.17%	4.21%	3.69%	3.42%	2.39%	3.42%	3.00%	3.06%	2.87%	2.65%	3.02%	3.76%
TGRNX TIAA-CREF Green Bond Fund	4.30%	4.31%	4.48%	3.30%	2.69%	2.76%	4.20%	4.38%	0.43%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both MRBIX and TGRNX in my portfolio?

With a correlation of 0.93, MRBIX and TGRNX 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, MRBIX or TGRNX?

MRBIX has higher volatility (1.30%) compared to TGRNX (1.06%). In terms of maximum drawdown, MRBIX dropped -19.25% vs TGRNX's -17.85%.

Which has better risk-adjusted returns?

TGRNX currently has the higher Sharpe Ratio (1.66 vs 1.42), 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.