TARKX vs. COST

Last updated Jul 14, 2026

TARKX (Tarkio Fund) is Mid Cap Blend Equities fund managed by Clark Fork Trust, while COST (Costco Wholesale Corporation) is a stock. Over the past 10 years, TARKX returned 14.73%/yr vs 20.76%/yr for COST. At a 0.38 correlation, their price movements are largely independent.

Performance

TARKX vs. COST - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Tarkio Fund (TARKX) and Costco Wholesale Corporation (COST). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, TARKX achieves a 21.55% return, which is significantly higher than COST's 7.73% return. Over the past 10 years, TARKX has underperformed COST with an annualized return of 14.73%, while COST has yielded a comparatively higher 20.76% annualized return.

TARKX

• 1D: 0.99%
• 1M: 1.69%
• 6M: 15.91%
• YTD: 21.55%
• 1Y: 46.91%
• 3Y*: 25.57%
• 5Y*: 11.21%
• 10Y*: 14.73%

COST

• 1D: 1.11%
• 1M: -5.69%
• 6M: -1.49%
• YTD: 7.73%
• 1Y: -3.99%
• 3Y*: 20.82%
• 5Y*: 18.99%
• 10Y*: 20.76%

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

TARKX vs. COST - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
TARKX Tarkio Fund	21.55%	30.18%	21.72%	26.33%	-30.39%	24.41%	27.00%	29.54%	-23.30%	29.04%
COST Costco Wholesale Corporation	7.73%	-5.39%	39.62%	49.00%	-19.05%	51.82%	32.67%	45.70%	10.60%	22.37%

Correlation

The correlation between TARKX and COST is -0.09, meaning there is essentially no relationship between their price movements. Each responds to its own set of market drivers, making them strong candidates for combining in a diversified portfolio.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	-0.09
Correlation (3Y) Calculated over the trailing 3-year period	0.18
Correlation (5Y) Calculated over the trailing 5-year period	0.33
Correlation (10Y) Calculated over the trailing 10-year period	0.34
Correlation (All Time) Calculated using the full available price history since Jun 30, 2011	0.38

The correlation between TARKX and COST shifts across timeframes, from -0.09 (1 year) to 0.38 (all time), reflecting how their relationship changes across market environments.

Return for Risk

TARKX vs. COST — Risk / Return Rank

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

TARKX

TARKX Risk / Return Rank: 56
TARKX Sharpe Ratio Rank: 50
TARKX Sortino Ratio Rank: 46
TARKX Omega Ratio Rank: 43
TARKX Calmar Ratio Rank: 75
TARKX Martin Ratio Rank: 64

COST

COST Risk / Return Rank: 34
COST Sharpe Ratio Rank: 36
COST Sortino Ratio Rank: 30
COST Omega Ratio Rank: 31
COST Calmar Ratio Rank: 37
COST Martin Ratio Rank: 35

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.

TARKX vs. COST - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Tarkio Fund (TARKX) and Costco Wholesale Corporation (COST). 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.

	TARKX	COST	Difference
Sharpe ratio: Return per unit of total volatility	1.59	-0.20	+1.79
Sortino ratio: Return per unit of downside risk	2.20	-0.15	+2.35
Omega ratio: Gain probability vs. loss probability	1.27	0.98	+0.29
Calmar ratio: Return relative to maximum drawdown	2.70	-0.24	+2.94
Martin ratio: Return relative to average drawdown	9.67	-0.56	+10.23

TARKX vs. COST - Sharpe Ratio Comparison

The current TARKX Sharpe Ratio is 1.59, which is higher than the COST Sharpe Ratio of -0.20. The chart below compares the historical Sharpe Ratios of TARKX and COST, 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

TARKX vs. COST - Drawdown Comparison

The maximum TARKX drawdown since its inception was -40.55%, smaller than the maximum COST drawdown of -53.39%. Use the drawdown chart below to compare losses from any high point for TARKX and COST.

Drawdown Indicators

	TARKX	COST	Difference
Max Drawdown Largest peak-to-trough decline	-40.55%	-53.39%	+12.84%
Max Drawdown (1Y) Largest decline over 1 year	-16.99%	-16.57%	-0.42%
Max Drawdown (3Y) Largest decline over 3 years	-36.99%	-20.74%	-16.25%
Max Drawdown (5Y) Largest decline over 5 years	-40.38%	-31.40%	-8.98%
Max Drawdown (10Y) Largest decline over 10 years	-40.55%	-31.40%	-9.15%
Current Drawdown Current decline from peak	-4.65%	-15.34%	+10.69%
Average Drawdown Average peak-to-trough decline	-10.32%	-13.36%	+3.04%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.74%	7.14%	-2.40%

Volatility

TARKX vs. COST - Volatility Comparison

Tarkio Fund (TARKX) has a higher volatility of 9.87% compared to Costco Wholesale Corporation (COST) at 6.82%. This indicates that TARKX's price experiences larger fluctuations and is considered to be riskier than COST based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TARKX	COST	Difference
Volatility (1M) Calculated over the trailing 1-month period	9.87%	6.82%	+3.05%
Volatility (6M) Calculated over the trailing 6-month period	22.37%	14.82%	+7.55%
Volatility (1Y) Calculated over the trailing 1-year period	28.94%	19.61%	+9.33%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	27.81%	22.86%	+4.95%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	26.75%	21.99%	+4.76%

Dividends

TARKX vs. COST - Dividend Comparison

TARKX's dividend yield for the trailing twelve months is around 4.53%, more than COST's 0.58% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
COST Costco Wholesale Corporation	0.58%	0.59%	0.49%	2.87%	0.76%	0.54%	3.38%	0.86%	1.08%	4.81%	1.09%	4.06%
TARKX Tarkio Fund	4.53%	5.50%	1.51%	2.98%	10.62%	1.40%	0.50%	5.21%	3.34%	1.70%	0.47%	0.36%

Frequently Asked Questions

Can I hold both TARKX and COST in my portfolio?

TARKX and COST have a correlation of -0.09, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, TARKX or COST?

TARKX has higher volatility (9.87%) compared to COST (6.82%). In terms of maximum drawdown, TARKX dropped -40.55% vs COST's -53.39%.

Which has better risk-adjusted returns?

TARKX currently has the higher Sharpe Ratio (1.59 vs -0.20), 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.