AMBFX vs. TIBIX

Last updated Jun 4, 2026

AMBFX (American Funds American Balanced Fund® Class F-2) and TIBIX (Thornburg Investment Income Builder Fund Class I) are both Diversified Portfolio funds. Over the past 10 years, AMBFX returned 10.47%/yr vs 12.73%/yr for TIBIX. Their correlation of 0.81 suggests significant overlap in exposure. AMBFX charges 0.35%/yr vs 0.93%/yr for TIBIX.

Performance

AMBFX vs. TIBIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Funds American Balanced Fund® Class F-2 (AMBFX) and Thornburg Investment Income Builder Fund Class I (TIBIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, AMBFX achieves a 10.06% return, which is significantly lower than TIBIX's 17.96% return. Over the past 10 years, AMBFX has underperformed TIBIX with an annualized return of 10.47%, while TIBIX has yielded a comparatively higher 12.73% annualized return.

AMBFX

• 1D: 0.24%
• 1M: 4.00%
• YTD: 10.06%
• 6M: 10.70%
• 1Y: 25.21%
• 3Y*: 17.77%
• 5Y*: 9.94%
• 10Y*: 10.47%

TIBIX

• 1D: 0.65%
• 1M: 3.13%
• YTD: 17.96%
• 6M: 21.37%
• 1Y: 39.83%
• 3Y*: 26.83%
• 5Y*: 16.44%
• 10Y*: 12.73%

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

AMBFX vs. TIBIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
AMBFX American Funds American Balanced Fund® Class F-2	10.06%	18.67%	15.25%	13.81%	-11.93%	16.00%	11.06%	19.45%	-2.69%	14.85%
TIBIX Thornburg Investment Income Builder Fund Class I	17.96%	37.01%	13.48%	18.28%	-7.69%	20.36%	-0.40%	18.01%	-4.31%	15.23%

Correlation

The correlation between AMBFX and TIBIX is 0.60, 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	0.60
Correlation (3Y) Calculated over the trailing 3-year period	0.67
Correlation (5Y) Calculated over the trailing 5-year period	0.74
Correlation (10Y) Calculated over the trailing 10-year period	0.76
Correlation (All Time) Calculated using the full available price history since Aug 4, 2008	0.81

Over the past year, the correlation between AMBFX and TIBIX has dropped to 0.60 - well below their long-term average of 0.81, suggesting their price drivers have been diverging.

Return for Risk

AMBFX vs. TIBIX — Risk / Return Rank

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

AMBFX

AMBFX Risk / Return Rank: 86
AMBFX Sharpe Ratio Rank: 90
AMBFX Sortino Ratio Rank: 87
AMBFX Omega Ratio Rank: 84
AMBFX Calmar Ratio Rank: 81
AMBFX Martin Ratio Rank: 86

TIBIX

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

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.

AMBFX vs. TIBIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Funds American Balanced Fund® Class F-2 (AMBFX) and Thornburg Investment Income Builder Fund Class I (TIBIX). 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.

	AMBFX	TIBIX	Difference
Sharpe ratio: Return per unit of total volatility	2.96	4.77	-1.81
Sortino ratio: Return per unit of downside risk	4.14	6.85	-2.71
Omega ratio: Gain probability vs. loss probability	1.57	1.96	-0.40
Calmar ratio: Return relative to maximum drawdown	3.70	7.48	-3.78
Martin ratio: Return relative to average drawdown	16.73	29.20	-12.47
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

AMBFX vs. TIBIX - Sharpe Ratio Comparison

The current AMBFX Sharpe Ratio is 2.96, which is lower than the TIBIX Sharpe Ratio of 4.77. The chart below compares the historical Sharpe Ratios of AMBFX and TIBIX, 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

	AMBFX	TIBIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.96	4.77	-1.81
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.95	1.48	-0.53
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.98	0.95	+0.04
Sharpe Ratio (All Time) Calculated using the full available price history	0.78	0.77	+0.01

Drawdowns

AMBFX vs. TIBIX - Drawdown Comparison

The maximum AMBFX drawdown since its inception was -35.05%, smaller than the maximum TIBIX drawdown of -48.88%. Use the drawdown chart below to compare losses from any high point for AMBFX and TIBIX.

Drawdown Indicators

	AMBFX	TIBIX	Difference
Max Drawdown Largest peak-to-trough decline	-35.05%	-48.88%	+13.83%
Max Drawdown (1Y) Largest decline over 1 year	-7.00%	-5.39%	-1.61%
Max Drawdown (3Y) Largest decline over 3 years	-10.64%	-9.23%	-1.41%
Max Drawdown (5Y) Largest decline over 5 years	-18.65%	-20.79%	+2.14%
Max Drawdown (10Y) Largest decline over 10 years	-22.31%	-34.85%	+12.54%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-3.58%	-5.96%	+2.38%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.54%	1.38%	+0.16%

Volatility

AMBFX vs. TIBIX - Volatility Comparison

The current volatility for American Funds American Balanced Fund® Class F-2 (AMBFX) is 2.67%, while Thornburg Investment Income Builder Fund Class I (TIBIX) has a volatility of 3.12%. This indicates that AMBFX experiences smaller price fluctuations and is considered to be less risky than TIBIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	AMBFX	TIBIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.67%	3.12%	-0.45%
Volatility (6M) Calculated over the trailing 6-month period	6.86%	6.99%	-0.13%
Volatility (1Y) Calculated over the trailing 1-year period	8.73%	8.46%	+0.27%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	10.50%	11.16%	-0.66%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	10.67%	13.50%	-2.83%

AMBFX vs. TIBIX - Expense Ratio Comparison

AMBFX has a 0.35% expense ratio, which is lower than TIBIX's 0.93% expense ratio.

Dividends

AMBFX vs. TIBIX - Dividend Comparison

AMBFX's dividend yield for the trailing twelve months is around 7.72%, more than TIBIX's 5.03% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AMBFX American Funds American Balanced Fund® Class F-2	7.72%	8.47%	7.40%	2.20%	2.52%	4.50%	4.56%	4.19%	6.20%	4.85%	4.46%	5.81%
TIBIX Thornburg Investment Income Builder Fund Class I	5.03%	5.83%	5.67%	4.89%	5.89%	5.33%	4.31%	4.46%	4.77%	4.52%	4.14%	4.66%

Frequently Asked Questions

Can I hold both AMBFX and TIBIX in my portfolio?

AMBFX and TIBIX have a correlation of 0.60, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, AMBFX or TIBIX?

TIBIX has higher volatility (3.12%) compared to AMBFX (2.67%). In terms of maximum drawdown, AMBFX dropped -35.05% vs TIBIX's -48.88%.

Which has better risk-adjusted returns?

TIBIX currently has the higher Sharpe Ratio (4.77 vs 2.96), 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.