RBBAX vs. CSTAX

Last updated Jun 5, 2026

RBBAX (Columbia Income Builder Fund) and CSTAX (American Funds College 2027 Fund) are both Diversified Portfolio funds. Over the past 10 years, RBBAX returned 5.25%/yr vs 4.97%/yr for CSTAX. Their correlation of 0.89 suggests significant overlap in exposure. RBBAX charges 0.37%/yr vs 0.41%/yr for CSTAX.

Performance

RBBAX vs. CSTAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Columbia Income Builder Fund (RBBAX) and American Funds College 2027 Fund (CSTAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, RBBAX achieves a 3.67% return, which is significantly higher than CSTAX's 1.30% return. Over the past 10 years, RBBAX has outperformed CSTAX with an annualized return of 5.25%, while CSTAX has yielded a comparatively lower 4.97% annualized return.

RBBAX

• 1D: -0.32%
• 1M: 0.87%
• YTD: 3.67%
• 6M: 4.10%
• 1Y: 11.14%
• 3Y*: 8.99%
• 5Y*: 3.03%
• 10Y*: 5.25%

CSTAX

• 1D: -0.16%
• 1M: 0.40%
• YTD: 1.30%
• 6M: 1.67%
• 1Y: 6.47%
• 3Y*: 6.81%
• 5Y*: 2.74%
• 10Y*: 4.97%

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

RBBAX vs. CSTAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
RBBAX Columbia Income Builder Fund	3.67%	11.15%	4.96%	9.02%	-12.87%	6.08%	10.15%	13.77%	-2.66%	7.51%
CSTAX American Funds College 2027 Fund	1.30%	9.00%	5.57%	6.57%	-9.87%	6.52%	7.66%	13.35%	-2.23%	11.77%

Correlation

The correlation between RBBAX and CSTAX is 0.89, 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	0.89
Correlation (3Y) Calculated over the trailing 3-year period	0.92
Correlation (5Y) Calculated over the trailing 5-year period	0.92
Correlation (10Y) Calculated over the trailing 10-year period	0.90
Correlation (All Time) Calculated using the full available price history since Jan 3, 2013	0.89

The correlation between RBBAX and CSTAX has been stable across timeframes, ranging from 0.89 to 0.92 - a consistent structural relationship.

Return for Risk

RBBAX vs. CSTAX — Risk / Return Rank

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

RBBAX

RBBAX Risk / Return Rank: 71
RBBAX Sharpe Ratio Rank: 78
RBBAX Sortino Ratio Rank: 78
RBBAX Omega Ratio Rank: 77
RBBAX Calmar Ratio Rank: 61
RBBAX Martin Ratio Rank: 63

CSTAX

CSTAX Risk / Return Rank: 56
CSTAX Sharpe Ratio Rank: 59
CSTAX Sortino Ratio Rank: 66
CSTAX Omega Ratio Rank: 65
CSTAX Calmar Ratio Rank: 44
CSTAX Martin Ratio Rank: 47

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.

RBBAX vs. CSTAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Columbia Income Builder Fund (RBBAX) and American Funds College 2027 Fund (CSTAX). 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.

	RBBAX	CSTAX	Difference
Sharpe ratio: Return per unit of total volatility	2.52	2.25	+0.27
Sortino ratio: Return per unit of downside risk	3.69	3.38	+0.31
Omega ratio: Gain probability vs. loss probability	1.49	1.45	+0.05
Calmar ratio: Return relative to maximum drawdown	2.92	2.52	+0.40
Martin ratio: Return relative to average drawdown	11.97	9.68	+2.29
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

RBBAX vs. CSTAX - Sharpe Ratio Comparison

The current RBBAX Sharpe Ratio is 2.52, which is comparable to the CSTAX Sharpe Ratio of 2.25. The chart below compares the historical Sharpe Ratios of RBBAX and CSTAX, 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

	RBBAX	CSTAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.52	2.25	+0.27
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.48	0.53	-0.05
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.90	0.86	+0.04
Sharpe Ratio (All Time) Calculated using the full available price history	0.84	0.87	-0.03

Drawdowns

RBBAX vs. CSTAX - Drawdown Comparison

The maximum RBBAX drawdown since its inception was -23.23%, which is greater than CSTAX's maximum drawdown of -14.52%. Use the drawdown chart below to compare losses from any high point for RBBAX and CSTAX.

Drawdown Indicators

	RBBAX	CSTAX	Difference
Max Drawdown Largest peak-to-trough decline	-23.23%	-14.52%	-8.71%
Max Drawdown (1Y) Largest decline over 1 year	-3.93%	-2.72%	-1.21%
Max Drawdown (3Y) Largest decline over 3 years	-6.83%	-4.89%	-1.94%
Max Drawdown (5Y) Largest decline over 5 years	-18.06%	-14.52%	-3.54%
Max Drawdown (10Y) Largest decline over 10 years	-18.06%	-14.52%	-3.54%
Current Drawdown Current decline from peak	-0.32%	-0.56%	+0.24%
Average Drawdown Average peak-to-trough decline	-2.99%	-2.35%	-0.64%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.96%	0.71%	+0.25%

Volatility

RBBAX vs. CSTAX - Volatility Comparison

Columbia Income Builder Fund (RBBAX) has a higher volatility of 1.54% compared to American Funds College 2027 Fund (CSTAX) at 1.10%. This indicates that RBBAX's price experiences larger fluctuations and is considered to be riskier than CSTAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	RBBAX	CSTAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.54%	1.10%	+0.44%
Volatility (6M) Calculated over the trailing 6-month period	3.56%	2.31%	+1.25%
Volatility (1Y) Calculated over the trailing 1-year period	4.55%	3.04%	+1.51%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.31%	5.16%	+1.15%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.83%	5.79%	+0.04%

RBBAX vs. CSTAX - Expense Ratio Comparison

RBBAX has a 0.37% expense ratio, which is lower than CSTAX's 0.41% expense ratio.

Dividends

RBBAX vs. CSTAX - Dividend Comparison

RBBAX's dividend yield for the trailing twelve months is around 3.59%, less than CSTAX's 5.20% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
CSTAX American Funds College 2027 Fund	5.20%	5.26%	3.78%	3.17%	3.40%	7.52%	5.72%	4.00%	4.78%	3.90%	4.34%	4.49%
RBBAX Columbia Income Builder Fund	3.59%	3.85%	3.95%	3.82%	4.94%	4.73%	4.07%	3.90%	3.92%	3.47%	3.01%	6.84%

Frequently Asked Questions

Can I hold both RBBAX and CSTAX in my portfolio?

RBBAX and CSTAX have a correlation of 0.89, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, RBBAX or CSTAX?

RBBAX has higher volatility (1.54%) compared to CSTAX (1.10%). In terms of maximum drawdown, RBBAX dropped -23.23% vs CSTAX's -14.52%.

Which has better risk-adjusted returns?

RBBAX currently has the higher Sharpe Ratio (2.52 vs 2.25), 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.