TWTIX vs. OAKMX

Last updated Jun 4, 2026

TWTIX (American Century Intermediate-Term Tax-Free Bond Fund) and OAKMX (Oakmark Fund Investor Class) are both mutual funds - TWTIX is a Municipal Bonds fund managed by American Century, while OAKMX is a Large Cap Value Equities fund managed by Oakmark. Over the past 10 years, TWTIX returned 2.13%/yr vs 13.40%/yr for OAKMX. At a correlation of -0.04, they often move in opposite directions. TWTIX charges 0.46%/yr vs 0.91%/yr for OAKMX.

Performance

TWTIX vs. OAKMX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Intermediate-Term Tax-Free Bond Fund (TWTIX) and Oakmark Fund Investor Class (OAKMX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, TWTIX achieves a 1.29% return, which is significantly higher than OAKMX's -0.93% return. Over the past 10 years, TWTIX has underperformed OAKMX with an annualized return of 2.13%, while OAKMX has yielded a comparatively higher 13.40% annualized return.

TWTIX

• 1D: 0.09%
• 1M: 0.55%
• YTD: 1.29%
• 6M: 1.68%
• 1Y: 6.60%
• 3Y*: 4.12%
• 5Y*: 1.10%
• 10Y*: 2.13%

OAKMX

• 1D: -0.79%
• 1M: -0.39%
• YTD: -0.93%
• 6M: 2.09%
• 1Y: 11.45%
• 3Y*: 15.03%
• 5Y*: 9.46%
• 10Y*: 13.40%

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

TWTIX vs. OAKMX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
TWTIX American Century Intermediate-Term Tax-Free Bond Fund	1.29%	5.15%	2.23%	5.43%	-8.50%	1.83%	4.78%	6.93%	0.93%	4.78%
OAKMX Oakmark Fund Investor Class	-0.93%	14.13%	16.02%	30.92%	-13.38%	34.85%	12.90%	27.14%	-12.76%	21.12%

Correlation

The correlation between TWTIX and OAKMX is 0.12, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.12
Correlation (3Y) Calculated over the trailing 3-year period	0.13
Correlation (5Y) Calculated over the trailing 5-year period	0.08
Correlation (10Y) Calculated over the trailing 10-year period	-0.03
Correlation (All Time) Calculated using the full available price history since Aug 6, 1991	-0.04

The correlation between TWTIX and OAKMX shifts across timeframes, from -0.04 (all time) to 0.13 (3 years), reflecting how their relationship changes across market environments.

Return for Risk

TWTIX vs. OAKMX — Risk / Return Rank

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

TWTIX

TWTIX Risk / Return Rank: 68
TWTIX Sharpe Ratio Rank: 84
TWTIX Sortino Ratio Rank: 90
TWTIX Omega Ratio Rank: 93
TWTIX Calmar Ratio Rank: 37
TWTIX Martin Ratio Rank: 34

OAKMX

OAKMX Risk / Return Rank: 15
OAKMX Sharpe Ratio Rank: 12
OAKMX Sortino Ratio Rank: 13
OAKMX Omega Ratio Rank: 12
OAKMX Calmar Ratio Rank: 23
OAKMX Martin Ratio Rank: 16

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.

TWTIX vs. OAKMX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Intermediate-Term Tax-Free Bond Fund (TWTIX) and Oakmark Fund Investor Class (OAKMX). 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.

	TWTIX	OAKMX	Difference
Sharpe ratio Return per unit of total volatility	2.75	0.95	+1.80
Sortino ratio Return per unit of downside risk	4.38	1.44	+2.95
Omega ratio Gain probability vs. loss probability	1.73	1.17	+0.56
Calmar ratio Return relative to maximum drawdown	2.31	1.76	+0.55
Martin ratio Return relative to average drawdown	7.72	4.53	+3.20
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

TWTIX vs. OAKMX - Sharpe Ratio Comparison

The current TWTIX Sharpe Ratio is 2.75, which is higher than the OAKMX Sharpe Ratio of 0.95. The chart below compares the historical Sharpe Ratios of TWTIX and OAKMX, 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

	TWTIX	OAKMX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.75	0.95	+1.80
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.34	0.52	-0.18
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.61	0.66	-0.05
Sharpe Ratio (All Time) Calculated using the full available price history	1.37	0.71	+0.66

Drawdowns

TWTIX vs. OAKMX - Drawdown Comparison

The maximum TWTIX drawdown since its inception was -12.57%, smaller than the maximum OAKMX drawdown of -56.19%. Use the drawdown chart below to compare losses from any high point for TWTIX and OAKMX.

Drawdown Indicators

	TWTIX	OAKMX	Difference
Max Drawdown Largest peak-to-trough decline	-12.57%	-56.19%	+43.62%
Max Drawdown (1Y) Largest decline over 1 year	-2.82%	-6.98%	+4.16%
Max Drawdown (3Y) Largest decline over 3 years	-4.76%	-17.05%	+12.29%
Max Drawdown (5Y) Largest decline over 5 years	-12.57%	-23.68%	+11.11%
Max Drawdown (10Y) Largest decline over 10 years	-12.57%	-41.43%	+28.86%
Current Drawdown Current decline from peak	-0.83%	-3.47%	+2.64%
Average Drawdown Average peak-to-trough decline	-1.51%	-6.39%	+4.88%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.84%	2.71%	-1.87%

Volatility

TWTIX vs. OAKMX - Volatility Comparison

The current volatility for American Century Intermediate-Term Tax-Free Bond Fund (TWTIX) is 0.92%, while Oakmark Fund Investor Class (OAKMX) has a volatility of 2.93%. This indicates that TWTIX experiences smaller price fluctuations and is considered to be less risky than OAKMX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TWTIX	OAKMX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.92%	2.93%	-2.01%
Volatility (6M) Calculated over the trailing 6-month period	1.84%	9.34%	-7.50%
Volatility (1Y) Calculated over the trailing 1-year period	2.37%	13.00%	-10.63%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	3.29%	18.29%	-15.00%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	3.53%	20.40%	-16.87%

TWTIX vs. OAKMX - Expense Ratio Comparison

TWTIX has a 0.46% expense ratio, which is lower than OAKMX's 0.91% expense ratio.

Dividends

TWTIX vs. OAKMX - Dividend Comparison

TWTIX's dividend yield for the trailing twelve months is around 3.36%, more than OAKMX's 0.93% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
OAKMX Oakmark Fund Investor Class	0.93%	0.92%	1.12%	1.02%	0.92%	1.94%	0.17%	8.33%	8.13%	4.06%	2.58%	1.43%
TWTIX American Century Intermediate-Term Tax-Free Bond Fund	3.36%	3.93%	3.79%	2.98%	1.93%	1.99%	2.32%	2.72%	2.70%	2.61%	2.54%	2.61%

Frequently Asked Questions

Can I hold both TWTIX and OAKMX in my portfolio?

TWTIX and OAKMX have a correlation of 0.12, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, TWTIX or OAKMX?

OAKMX has higher volatility (2.93%) compared to TWTIX (0.92%). In terms of maximum drawdown, TWTIX dropped -12.57% vs OAKMX's -56.19%.

Which has better risk-adjusted returns?

TWTIX currently has the higher Sharpe Ratio (2.75 vs 0.95), 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.