TIBAX vs. AMECX

Last updated Jun 4, 2026

TIBAX (Thornburg Investment Income Builder Fund) and AMECX (American Funds The Income Fund of America Class A) are both mutual funds - TIBAX is a Global Allocation fund managed by Thornburg, while AMECX is a Diversified Portfolio fund managed by American Funds. Over the past 10 years, TIBAX returned 12.42%/yr vs 8.51%/yr for AMECX. Their correlation of 0.86 suggests significant overlap in exposure. TIBAX charges 1.14%/yr vs 0.56%/yr for AMECX.

Performance

TIBAX vs. AMECX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Thornburg Investment Income Builder Fund (TIBAX) and American Funds The Income Fund of America Class A (AMECX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, TIBAX achieves a 17.92% return, which is significantly higher than AMECX's 6.34% return. Over the past 10 years, TIBAX has outperformed AMECX with an annualized return of 12.42%, while AMECX has yielded a comparatively lower 8.51% annualized return.

TIBAX

• 1D: 0.63%
• 1M: 3.10%
• YTD: 17.92%
• 6M: 21.20%
• 1Y: 39.47%
• 3Y*: 26.52%
• 5Y*: 16.15%
• 10Y*: 12.42%

AMECX

• 1D: 0.33%
• 1M: 0.95%
• YTD: 6.34%
• 6M: 7.37%
• 1Y: 15.78%
• 3Y*: 13.76%
• 5Y*: 7.77%
• 10Y*: 8.51%

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

TIBAX vs. AMECX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
TIBAX Thornburg Investment Income Builder Fund	17.92%	36.62%	13.23%	18.01%	-7.95%	20.08%	-0.67%	17.72%	-4.54%	14.83%
AMECX American Funds The Income Fund of America Class A	6.34%	17.77%	10.84%	6.79%	-6.40%	17.37%	4.49%	18.50%	-5.27%	12.58%

Correlation

The correlation between TIBAX and AMECX is 0.71, 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	0.71
Correlation (3Y) Calculated over the trailing 3-year period	0.80
Correlation (5Y) Calculated over the trailing 5-year period	0.83
Correlation (10Y) Calculated over the trailing 10-year period	0.85
Correlation (All Time) Calculated using the full available price history since Dec 26, 2002	0.86

The correlation between TIBAX and AMECX shifts across timeframes, from 0.71 (1 year) to 0.86 (all time), reflecting how their relationship changes across market environments.

Return for Risk

TIBAX vs. AMECX — Risk / Return Rank

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

TIBAX

TIBAX Risk / Return Rank: 98
TIBAX Sharpe Ratio Rank: 99
TIBAX Sortino Ratio Rank: 98
TIBAX Omega Ratio Rank: 97
TIBAX Calmar Ratio Rank: 97
TIBAX Martin Ratio Rank: 98

AMECX

AMECX Risk / Return Rank: 53
AMECX Sharpe Ratio Rank: 58
AMECX Sortino Ratio Rank: 56
AMECX Omega Ratio Rank: 55
AMECX Calmar Ratio Rank: 47
AMECX Martin Ratio Rank: 48

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.

TIBAX vs. AMECX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Thornburg Investment Income Builder Fund (TIBAX) and American Funds The Income Fund of America Class A (AMECX). 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.

	TIBAX	AMECX	Difference
Sharpe ratio: Return per unit of total volatility	4.75	2.24	+2.51
Sortino ratio: Return per unit of downside risk	6.82	3.16	+3.66
Omega ratio: Gain probability vs. loss probability	1.96	1.41	+0.55
Calmar ratio: Return relative to maximum drawdown	7.36	2.62	+4.74
Martin ratio: Return relative to average drawdown	28.70	9.88	+18.83
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

TIBAX vs. AMECX - Sharpe Ratio Comparison

The current TIBAX Sharpe Ratio is 4.75, which is higher than the AMECX Sharpe Ratio of 2.24. The chart below compares the historical Sharpe Ratios of TIBAX and AMECX, 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

	TIBAX	AMECX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	4.75	2.24	+2.51
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	1.46	0.83	+0.63
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.93	0.80	+0.13
Sharpe Ratio (All Time) Calculated using the full available price history	0.80	0.72	+0.07

Drawdowns

TIBAX vs. AMECX - Drawdown Comparison

The maximum TIBAX drawdown since its inception was -49.12%, which is greater than AMECX's maximum drawdown of -41.92%. Use the drawdown chart below to compare losses from any high point for TIBAX and AMECX.

Drawdown Indicators

	TIBAX	AMECX	Difference
Max Drawdown Largest peak-to-trough decline	-49.12%	-41.92%	-7.20%
Max Drawdown (1Y) Largest decline over 1 year	-5.43%	-6.13%	+0.70%
Max Drawdown (3Y) Largest decline over 3 years	-9.20%	-8.58%	-0.62%
Max Drawdown (5Y) Largest decline over 5 years	-20.94%	-15.78%	-5.16%
Max Drawdown (10Y) Largest decline over 10 years	-34.85%	-26.13%	-8.72%
Current Drawdown Current decline from peak	0.00%	-1.23%	+1.23%
Average Drawdown Average peak-to-trough decline	-5.99%	-4.45%	-1.54%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.39%	1.62%	-0.23%

Volatility

TIBAX vs. AMECX - Volatility Comparison

Thornburg Investment Income Builder Fund (TIBAX) has a higher volatility of 3.12% compared to American Funds The Income Fund of America Class A (AMECX) at 2.06%. This indicates that TIBAX's price experiences larger fluctuations and is considered to be riskier than AMECX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TIBAX	AMECX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.12%	2.06%	+1.06%
Volatility (6M) Calculated over the trailing 6-month period	6.97%	5.63%	+1.34%
Volatility (1Y) Calculated over the trailing 1-year period	8.42%	7.17%	+1.25%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	11.12%	9.45%	+1.67%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	13.46%	10.68%	+2.78%

TIBAX vs. AMECX - Expense Ratio Comparison

TIBAX has a 1.14% expense ratio, which is higher than AMECX's 0.56% expense ratio.

Dividends

TIBAX vs. AMECX - Dividend Comparison

TIBAX's dividend yield for the trailing twelve months is around 4.85%, less than AMECX's 9.41% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AMECX American Funds The Income Fund of America Class A	9.41%	9.94%	6.38%	2.93%	6.98%	6.67%	2.80%	5.01%	7.48%	4.26%	3.09%	5.09%
TIBAX Thornburg Investment Income Builder Fund	4.85%	5.64%	5.44%	4.67%	5.62%	5.10%	4.11%	4.23%	4.49%	4.22%	3.83%	4.31%

Frequently Asked Questions

Can I hold both TIBAX and AMECX in my portfolio?

TIBAX and AMECX have a correlation of 0.71, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, TIBAX or AMECX?

TIBAX has higher volatility (3.12%) compared to AMECX (2.06%). In terms of maximum drawdown, TIBAX dropped -49.12% vs AMECX's -41.92%.

Which has better risk-adjusted returns?

TIBAX currently has the higher Sharpe Ratio (4.75 vs 2.24), 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.