TSTFX vs. IAAAX

Last updated Jun 24, 2026

TSTFX (Transamerica Stock Index) and IAAAX (Transamerica Asset Allocation Growth Portfolio Fund) are both mutual funds - TSTFX is a Large Cap Blend Equities fund managed by Transamerica, while IAAAX is a Diversified Portfolio fund managed by Transamerica. Over the past 5 years, TSTFX returned 5.79%/yr vs 9.38%/yr for IAAAX. Their correlation of 0.90 suggests significant overlap in exposure. TSTFX charges 0.30%/yr vs 0.49%/yr for IAAAX.

Performance

TSTFX vs. IAAAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Transamerica Stock Index (TSTFX) and Transamerica Asset Allocation Growth Portfolio Fund (IAAAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both stocks are quite close, with TSTFX having a 9.60% return and IAAAX slightly lower at 9.34%.

TSTFX

• 1D: -0.40%
• 1M: 0.06%
• YTD: 9.60%
• 6M: 8.58%
• 1Y: -11.43%
• 3Y*: 7.80%
• 5Y*: 5.79%
• 10Y*: —

IAAAX

• 1D: -0.43%
• 1M: 1.26%
• YTD: 9.34%
• 6M: 8.45%
• 1Y: 24.54%
• 3Y*: 19.38%
• 5Y*: 9.38%
• 10Y*: 11.45%

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

TSTFX vs. IAAAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
TSTFX Transamerica Stock Index	9.60%	-17.03%	24.66%	25.99%	-18.27%	28.84%	18.10%	31.17%	-4.75%	14.78%
IAAAX Transamerica Asset Allocation Growth Portfolio Fund	9.34%	21.45%	17.37%	20.04%	-19.24%	16.14%	18.87%	21.75%	-11.48%	14.45%

Correlation

The correlation between TSTFX and IAAAX is 0.83, 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	0.83
Correlation (3Y) Calculated over the trailing 3-year period	0.84
Correlation (5Y) Calculated over the trailing 5-year period	0.89
Correlation (All Time) Calculated using the full available price history since Mar 22, 2017	0.90

The correlation between TSTFX and IAAAX has been stable across timeframes, ranging from 0.83 to 0.90 - a consistent structural relationship.

Return for Risk

TSTFX vs. IAAAX — Risk / Return Rank

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

TSTFX

TSTFX Risk / Return Rank: 1
TSTFX Sharpe Ratio Rank: 1
TSTFX Sortino Ratio Rank: 2
TSTFX Omega Ratio Rank: 1
TSTFX Calmar Ratio Rank: 1
TSTFX Martin Ratio Rank: 2

IAAAX

IAAAX Risk / Return Rank: 50
IAAAX Sharpe Ratio Rank: 48
IAAAX Sortino Ratio Rank: 46
IAAAX Omega Ratio Rank: 47
IAAAX Calmar Ratio Rank: 51
IAAAX Martin Ratio Rank: 61

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.

TSTFX vs. IAAAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Transamerica Stock Index (TSTFX) and Transamerica Asset Allocation Growth Portfolio Fund (IAAAX). 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.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	TSTFX	IAAAX	Difference
Sharpe ratio: Return per unit of total volatility	-0.37	1.88	-2.25
Sortino ratio: Return per unit of downside risk	-0.21	2.63	-2.83
Omega ratio: Gain probability vs. loss probability	0.93	1.34	-0.41
Calmar ratio: Return relative to maximum drawdown	-0.34	2.61	-2.95
Martin ratio: Return relative to average drawdown	-0.57	11.46	-12.03

TSTFX vs. IAAAX - Sharpe Ratio Comparison

The current TSTFX Sharpe Ratio is -0.37, which is lower than the IAAAX Sharpe Ratio of 1.88. The chart below compares the historical Sharpe Ratios of TSTFX and IAAAX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

TSTFX vs. IAAAX - Drawdown Comparison

The maximum TSTFX drawdown since its inception was -34.74%, smaller than the maximum IAAAX drawdown of -56.57%. Use the drawdown chart below to compare losses from any high point for TSTFX and IAAAX.

Drawdown Indicators

	TSTFX	IAAAX	Difference
Max Drawdown Largest peak-to-trough decline	-34.74%	-56.57%	+21.83%
Max Drawdown (1Y) Largest decline over 1 year	-34.74%	-9.85%	-24.89%
Max Drawdown (3Y) Largest decline over 3 years	-34.74%	-17.90%	-16.84%
Max Drawdown (5Y) Largest decline over 5 years	-34.74%	-29.29%	-5.45%
Max Drawdown (10Y) Largest decline over 10 years	—	-35.34%	—
Current Drawdown Current decline from peak	-22.96%	-0.91%	-22.05%
Average Drawdown Average peak-to-trough decline	-6.13%	-9.51%	+3.38%
Ulcer Index Depth and duration of drawdowns from previous peaks	19.62%	2.24%	+17.38%

Volatility

TSTFX vs. IAAAX - Volatility Comparison

The current volatility for Transamerica Stock Index (TSTFX) is 4.64%, while Transamerica Asset Allocation Growth Portfolio Fund (IAAAX) has a volatility of 4.97%. This indicates that TSTFX experiences smaller price fluctuations and is considered to be less risky than IAAAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TSTFX	IAAAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.64%	4.97%	-0.33%
Volatility (6M) Calculated over the trailing 6-month period	34.50%	10.96%	+23.54%
Volatility (1Y) Calculated over the trailing 1-year period	32.43%	13.68%	+18.75%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.58%	16.44%	+5.14%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.00%	16.90%	+4.10%

TSTFX vs. IAAAX - Expense Ratio Comparison

TSTFX has a 0.30% expense ratio, which is lower than IAAAX's 0.49% expense ratio.

Dividends

TSTFX vs. IAAAX - Dividend Comparison

TSTFX's dividend yield for the trailing twelve months is around 0.57%, less than IAAAX's 6.60% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
IAAAX Transamerica Asset Allocation Growth Portfolio Fund	6.60%	7.21%	5.16%	2.79%	8.74%	8.25%	4.13%	9.02%	19.05%	11.01%	8.16%	9.44%
TSTFX Transamerica Stock Index	0.57%	0.70%	2.61%	4.32%	6.77%	6.57%	4.69%	5.60%	4.69%	2.85%	0.00%	0.00%

Frequently Asked Questions

Can I hold both TSTFX and IAAAX in my portfolio?

TSTFX and IAAAX have a correlation of 0.83, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, TSTFX or IAAAX?

IAAAX has higher volatility (4.97%) compared to TSTFX (4.64%). In terms of maximum drawdown, TSTFX dropped -34.74% vs IAAAX's -56.57%.

Which has better risk-adjusted returns?

IAAAX currently has the higher Sharpe Ratio (1.88 vs -0.37), 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.