NPHIX vs. CPMPX

Last updated Jun 4, 2026

NPHIX (American Century High Income Fund) and CPMPX (Changing Parameters Fund) are both High Yield Bonds funds. Over the past 10 years, NPHIX returned 5.49%/yr vs 4.18%/yr for CPMPX. A 0.54 correlation means they provide meaningful diversification when combined. NPHIX charges 0.58%/yr vs 2.90%/yr for CPMPX.

Performance

NPHIX vs. CPMPX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century High Income Fund (NPHIX) and Changing Parameters Fund (CPMPX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, NPHIX achieves a 1.55% return, which is significantly higher than CPMPX's 0.85% return. Over the past 10 years, NPHIX has outperformed CPMPX with an annualized return of 5.49%, while CPMPX has yielded a comparatively lower 4.18% annualized return.

NPHIX

• 1D: 0.12%
• 1M: 0.45%
• YTD: 1.55%
• 6M: 2.12%
• 1Y: 7.70%
• 3Y*: 8.30%
• 5Y*: 3.53%
• 10Y*: 5.49%

CPMPX

• 1D: 0.00%
• 1M: 0.28%
• YTD: 0.85%
• 6M: 1.17%
• 1Y: 5.61%
• 3Y*: 3.46%
• 5Y*: 2.48%
• 10Y*: 4.18%

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

NPHIX vs. CPMPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
NPHIX American Century High Income Fund	1.55%	8.86%	6.92%	12.05%	-12.59%	6.12%	8.03%	12.70%	-1.98%	7.02%
CPMPX Changing Parameters Fund	0.85%	6.65%	-3.47%	8.13%	-0.22%	3.86%	13.43%	6.82%	-1.19%	5.29%

Correlation

The correlation between NPHIX and CPMPX is 0.58, 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	0.58
Correlation (3Y) Calculated over the trailing 3-year period	0.59
Correlation (5Y) Calculated over the trailing 5-year period	0.55
Correlation (10Y) Calculated over the trailing 10-year period	0.58
Correlation (All Time) Calculated using the full available price history since Jan 3, 2013	0.54

The correlation between NPHIX and CPMPX has been stable across timeframes, ranging from 0.54 to 0.59 - a consistent structural relationship.

Return for Risk

NPHIX vs. CPMPX — Risk / Return Rank

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

NPHIX

NPHIX Risk / Return Rank: 75
NPHIX Sharpe Ratio Rank: 62
NPHIX Sortino Ratio Rank: 84
NPHIX Omega Ratio Rank: 81
NPHIX Calmar Ratio Rank: 65
NPHIX Martin Ratio Rank: 83

CPMPX

CPMPX Risk / Return Rank: 88
CPMPX Sharpe Ratio Rank: 94
CPMPX Sortino Ratio Rank: 95
CPMPX Omega Ratio Rank: 95
CPMPX Calmar Ratio Rank: 89
CPMPX Martin Ratio Rank: 66

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.

NPHIX vs. CPMPX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century High Income Fund (NPHIX) and Changing Parameters Fund (CPMPX). 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.

	NPHIX	CPMPX	Difference
Sharpe ratio: Return per unit of total volatility	2.33	3.26	-0.93
Sortino ratio: Return per unit of downside risk	4.03	4.97	-0.94
Omega ratio: Gain probability vs. loss probability	1.53	1.80	-0.27
Calmar ratio: Return relative to maximum drawdown	3.11	4.48	-1.37
Martin ratio: Return relative to average drawdown	15.67	12.81	+2.85
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

NPHIX vs. CPMPX - Sharpe Ratio Comparison

The current NPHIX Sharpe Ratio is 2.33, which is comparable to the CPMPX Sharpe Ratio of 3.26. The chart below compares the historical Sharpe Ratios of NPHIX and CPMPX, 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

	NPHIX	CPMPX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.33	3.26	-0.93
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.67	0.65	+0.02
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.97	1.35	-0.37
Sharpe Ratio (All Time) Calculated using the full available price history	1.00	1.11	-0.10

Drawdowns

NPHIX vs. CPMPX - Drawdown Comparison

The maximum NPHIX drawdown since its inception was -21.67%, which is greater than CPMPX's maximum drawdown of -8.87%. Use the drawdown chart below to compare losses from any high point for NPHIX and CPMPX.

Drawdown Indicators

	NPHIX	CPMPX	Difference
Max Drawdown Largest peak-to-trough decline	-21.67%	-8.87%	-12.80%
Max Drawdown (1Y) Largest decline over 1 year	-2.52%	-1.31%	-1.21%
Max Drawdown (3Y) Largest decline over 3 years	-3.94%	-8.13%	+4.19%
Max Drawdown (5Y) Largest decline over 5 years	-16.34%	-8.13%	-8.21%
Max Drawdown (10Y) Largest decline over 10 years	-21.67%	-8.13%	-13.54%
Current Drawdown Current decline from peak	0.00%	-1.09%	+1.09%
Average Drawdown Average peak-to-trough decline	-2.52%	-1.87%	-0.65%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.50%	0.46%	+0.04%

Volatility

NPHIX vs. CPMPX - Volatility Comparison

American Century High Income Fund (NPHIX) has a higher volatility of 1.11% compared to Changing Parameters Fund (CPMPX) at 0.51%. This indicates that NPHIX's price experiences larger fluctuations and is considered to be riskier than CPMPX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	NPHIX	CPMPX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.11%	0.51%	+0.60%
Volatility (6M) Calculated over the trailing 6-month period	2.53%	1.29%	+1.24%
Volatility (1Y) Calculated over the trailing 1-year period	3.37%	1.80%	+1.57%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.28%	3.83%	+1.45%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.65%	3.11%	+2.54%

NPHIX vs. CPMPX - Expense Ratio Comparison

NPHIX has a 0.58% expense ratio, which is lower than CPMPX's 2.90% expense ratio.

Dividends

NPHIX vs. CPMPX - Dividend Comparison

NPHIX's dividend yield for the trailing twelve months is around 6.75%, more than CPMPX's 3.80% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
CPMPX Changing Parameters Fund	3.80%	3.83%	0.00%	4.26%	5.03%	4.24%	6.94%	2.85%	1.71%	3.32%	2.25%	1.51%
NPHIX American Century High Income Fund	6.75%	6.69%	6.07%	4.81%	4.95%	5.77%	5.35%	5.54%	6.24%	5.87%	5.72%	7.44%

Frequently Asked Questions

Can I hold both NPHIX and CPMPX in my portfolio?

NPHIX and CPMPX have a correlation of 0.58, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, NPHIX or CPMPX?

NPHIX has higher volatility (1.11%) compared to CPMPX (0.51%). In terms of maximum drawdown, NPHIX dropped -21.67% vs CPMPX's -8.87%.

Which has better risk-adjusted returns?

CPMPX currently has the higher Sharpe Ratio (3.26 vs 2.33), 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.