SNDK vs STX: Stock Returns, Risk & Volatility (2026)

Q: Which is a better investment: SNDK or STX?

Over the past year, SNDK looks like the better investment: it had higher total return (SNDK +1300.3% vs STX +327.0%) and a higher Sharpe ratio (SNDK 3.18 vs STX 2.61). On risk, STX was less volatile (STX 62.1% vs SNDK 98.0%), STX had a smaller max drawdown (STX -34.2% vs SNDK -47.5%), and STX had less severe losses on the worst 5% of days (Expected Shortfall of STX -8.02% vs SNDK -13.96%).

Written by Gale Finance Team

Reviewed by Sid Kalla CFA Charterholder

Quick answer

Which is a better investment: SNDK or STX?

Over the past year, SNDK outperformed (+1300.3% vs +327.0%) with a Sharpe ratio of 3.18.

Total Return

SNDK WIN +1300.3%

STX +327.0%

Sharpe Ratio

SNDK WIN 3.18

STX 2.61

Annualized Volatility

SNDK 98.0%

STX WIN 62.1%

Max Drawdown

SNDK -47.5%

STX WIN -34.2%

Analysis period: 2025-02-27 to 2026-02-25

SNDK Total Return

↑ +1300.3%

STX Total Return

↑ +327.0%

Relative Performance of SNDK vs STX (Normalized to 100)

SNDK STX

Normalized to 100 at start date for comparison

Key Takeaways

Total Return: SNDK delivered a +1300.3% total return, while STX returned +327.0% over the same period. SNDK outperformed on total returns.
Risk-Adjusted Return (Sharpe Ratio): SNDK had a higher Sharpe (3.18 vs 2.61), indicating better risk-adjusted performance.
Volatility (Annualized): SNDK was more volatile, with 98.0% annualized volatility, versus 62.1% for STX.
Maximum Drawdown: STX's maximum drawdown was -34.2%, while SNDK experienced a deeper drawdown of -47.5%.
Tail Risk (VaR & Expected Shortfall): At the 5% level (daily log returns), SNDK's VaR was -6.37% and its Expected Shortfall (CVaR) was -13.96%; STX's were -6.16% and -8.02%. VaR is the cutoff; Expected Shortfall is the average move on the worst days.
Skew & Kurtosis: Skew: SNDK -0.34 vs STX 0.30. Excess kurtosis: SNDK 3.30 vs STX 4.60. Negative skew leans downside; higher excess kurtosis means fatter tails.
Tail Days & Extremes: 2σ tail days (down/up): SNDK 7/8, STX 6/7. Worst day: SNDK -21.30% (2025-04-04) vs STX -16.36% (2025-04-03). Best day: SNDK +27.56% (2026-01-06) vs STX +19.14% (2026-01-28).
Risk ratios: Sortino - SNDK: 5.41 vs. STX: 4.50 , Calmar - SNDK: 27.86 vs. STX: 9.68 , Sterling - SNDK: 53.32 vs. STX: 18.40 , Treynor - SNDK: 1.29 vs. STX: 1.07 , Ulcer Index - SNDK: 20.85% vs. STX: 10.14%

Sandisk vs Seagate Technology Holdings plc Correlation

0.54 Average Correlation

Sandisk and Seagate Technology Holdings plc are moderately correlated over the past year. With a correlation of 0.54, these assets show moderate co-movement, offering some diversification when held together.

For portfolio construction, this moderate correlation offers some diversification benefit, though the assets still tend to move together during major market moves.

Metric	Value
Current (30-day)	0.53
Average (full period)	0.54
Minimum	0.08
Maximum	0.85

Correlation measures how closely two assets move together. Values near +1 indicate strong co-movement, near 0 indicates independence, and negative values indicate inverse movement.

Investment Comparison

If you invested $10,000 in each asset on February 27, 2025:

SNDK $140,031 +1300.3%

STX $42,703.05 +327.0%

Difference: $97,327.95 (SNDK ahead)

Sandisk and Seagate Technology Holdings plc: Risk Analysis

Sandisk experienced its maximum drawdown of -47.5% from 2025-03-18 to 2025-04-22. It took 135 days to recover.

Seagate Technology Holdings plc experienced its maximum drawdown of -34.2% from 2025-02-28 to 2025-04-08. It took 34 days to recover.

Smaller drawdowns and faster recoveries indicate lower downside risk and greater resilience during market stress.

Sharpe Ratio of SNDK and STX

SNDK Sharpe Ratio

↑ 3.18

STX Sharpe Ratio

↑ 2.61

Sharpe ratio measures return per unit of risk (volatility). A higher Sharpe indicates better risk-adjusted performance. SNDK had a higher Sharpe (3.18 vs 2.61), indicating better risk-adjusted performance.

A Sharpe above 1.0 is generally considered good, above 2.0 is excellent. Negative Sharpe means the asset underperformed the risk-free rate. Calculated on each asset's full 365-day lookback of available prices and annualized using the asset calendar (365 for crypto, 252 trading days for equities/ETFs/metals).

Sortino Ratio of SNDK and STX

SNDK Sortino Ratio

↑ 5.41

STX Sortino Ratio

↑ 4.50

Sortino ratio measures return per unit of downside risk. Unlike Sharpe, it only counts downside deviation (returns below the target return). SNDK had better downside-adjusted returns.

A higher Sortino is better. It's useful when upside volatility is common (crypto is the obvious example). Downside deviation: SNDK 57.6% vs STX 36.0%. Calculated on each asset's full 365-day lookback of available prices, using the daily risk-free rate as the target return, and annualized using the asset calendar (365 for crypto, 252 trading days for equities/ETFs/metals).

Calmar Ratio of SNDK and STX

SNDK Calmar Ratio

↑ 27.86

STX Calmar Ratio

↑ 9.68

Calmar ratio compares CAGR to maximum drawdown. Higher Calmar means more return per unit of worst drawdown. SNDK posted the higher Calmar ratio.

Calmar is computed on each asset's full 365-day lookback and uses the max drawdown over that same window.

Sterling Ratio of SNDK and STX

SNDK Sterling Ratio

↑ 53.32

STX Sterling Ratio

↑ 18.40

Sterling ratio measures excess return per unit of average drawdown (typically drawdowns worse than 10%). SNDK posted the higher Sterling ratio.

Sterling uses average drawdown events deeper than 10% and subtracts the risk-free rate to report excess return.

Treynor Ratio of SNDK and STX

SNDK Treynor Ratio

↑ 1.29

STX Treynor Ratio

↑ 1.07

Treynor ratio measures excess return per unit of market risk (beta) instead of total volatility. SNDK posted the higher Treynor ratio.

Treynor uses beta vs the S&P 500 (SPY) on shared dates and the average 3-month Treasury rate as the risk-free rate.

Ulcer Index of SNDK and STX

SNDK Ulcer Index

20.85%

STX Ulcer Index

10.14%

Ulcer Index captures drawdown depth and duration. Lower Ulcer Index means less drawdown pain. STX had the lower Ulcer Index (less drawdown pain).

Ulcer Index is computed from each asset's drawdown series over the full lookback window.

Tail Risk & Distribution Shape (1-Year): Sandisk vs. Seagate Technology Holdings plc

This section looks at the shape of daily returns, not just the average. Tail stats are computed per asset on its own daily series (crypto includes weekends). We use daily log returns $\ln\left(\frac{P_t}{P_{t-1}}\right)$ so multi-day moves add cleanly.

Definitions: Value at Risk (VaR), Expected Shortfall, skew, kurtosis, and fat tails.

Metric (1-Year)	SNDK	STX
5% VaR (daily log return)	-6.37%	-6.16%
5% Expected Shortfall (CVaR)	-13.96% (worst 13 days)	-8.02% (worst 13 days)
Skew	-0.34	0.30
Excess kurtosis	3.30	4.60
2σ tail days (down / up)	7 / 8	6 / 7
Worst day	-21.30% (2025-04-04)	-16.36% (2025-04-03)
Best day	+27.56% (2026-01-06)	+19.14% (2026-01-28)

Downside co-moves (2σ) — 1-Year

Computed on shared dates only (n=249). A “2σ downside move” means a shared-close log return more than 2 standard deviations below that asset’s own mean on this shared-date series. Dates below show simple returns (%) for readability.

When STX has a big down day, SNDK also does

50.0%

3 / 6 days

When SNDK has a big down day, STX also does

42.9%

3 / 7 days

Show downside tail dates

Dates below are shared-date observations. The “Date” is the period end (close). Tail thresholds are computed on log returns, but the table shows simple returns (%) for readability. Returns are computed from the previous shared close to this one (for example, Friday → Monday includes weekend moves).

Days when both SNDK and STX had a big down day (2σ)

Date (interval)	SNDK	STX
2025-04-03	-19.74%	-16.36%
2025-11-13	-13.96%	-7.31%
2025-11-20	-20.33%	-7.19%

Days when SNDK had a big down day

Date (interval)	SNDK	STX
2025-04-03	-19.74%	-16.36%
2025-04-04	-21.30%	-6.71%
2025-04-10	-15.05%	-6.12%
2025-11-13	-13.96%	-7.31%
2025-11-20	-20.33%	-7.19%
2025-12-12	-14.66%	-6.56%
2026-02-04	-15.95%	-5.81%

Days when STX had a big down day

Date (interval)	SNDK	STX
2025-04-03	-19.74%	-16.36%
2025-10-07	-0.18%	-7.34%
2025-11-13	-13.96%	-7.31%
2025-11-20	-20.33%	-7.19%
2026-01-08	-5.38%	-7.72%
2026-01-30	+6.85%	-8.71%

Read this as “how ugly the ugly days get”, not as a precise forecast. One-year samples are small, so tail estimates are inherently noisy.

Sandisk vs Seagate Technology Holdings plc Volatility (SNDK vs STX)

SNDK Volatility

98.0%

±6.18% daily

STX Volatility

62.1%

±3.91% daily

Typical daily swing

SNDK

±6.18%

STX

±3.91%

Sandisk's annualized volatility of 98.0% means it typically moves ±6.18% on any given day.

Seagate Technology Holdings plc's annualized volatility of 62.1% means it typically moves ±3.91% on any given day.

SNDK's higher volatility means a wider path to returns — this can be attractive for tactical, shorter-term exposure, while STX's smoother profile may better suit long-term allocators seeking steadier growth.

For comparison, the S&P 500 typically has 15-18% annualized volatility, translating to roughly ±1% daily moves. Higher volatility means larger potential gains but also larger potential losses.

Sandisk vs Seagate Technology Holdings plc Performance Over Time

Metric	SNDK	STX
30 Days	34.3%	17.7%
90 Days	194.1%	55.3%
180 Days	1105.2%	153.4%
1 Year	1300.3%	327%

Shorter time frames can show different leaders as market conditions change. Consider your investment horizon when comparing performance.

Full Comparison of Sandisk vs. Seagate Technology Holdings plc (1-Year)

Metric	SNDK	STX
Total Return	+1300.3%	+327.0%
Annualized Volatility	98.0%	62.1%
Sharpe Ratio	3.18	2.61
Sortino Ratio	5.41	4.50
Calmar Ratio	27.86	9.68
Sterling Ratio	53.32	18.40
Treynor Ratio	1.29	1.07
Ulcer Index	20.85%	10.14%
Max Drawdown	-47.5%	-34.2%
Avg Correlation to S&P 500	0.54	0.42
5% VaR (daily log return)	-6.37%	-6.16%
5% Expected Shortfall (CVaR)	-13.96%	-8.02%
Skew	-0.34	0.30
Excess kurtosis	3.30	4.60
2σ tail days (down / up)	7 / 8	6 / 7

Audit this calculation

Formulas, inputs, and conventions used to compute the metrics on this page.

Inputs & conventions

Shared window for pair metrics: 2025-02-27 → 2026-02-25 (last shared close).
Rolling correlation sample (shared closes): 220 rolling 30-day values (from 249 shared daily returns).
Annualization (days/year): SNDK: 252 days/year; STX: 252 days/year.
Risk-free rate: Uses the 3-month U.S. Treasury yield (FRED: DGS3MO), averaged over each asset’s window:

SNDK: 4.20% over 2025-02-27 → 2026-02-25.

STX: 4.20% over 2025-02-27 → 2026-02-25.
Volatility drag (rule of thumb): Estimated from annualized volatility (simple returns). For the log-return framing, see Log returns.

SNDK: ≈ -48.0%/yr

STX: ≈ -19.3%/yr
Data alignment: No forward fill. Correlation and tail co-moves are computed on shared closes only.
For cross-calendar pairs (e.g., crypto vs stocks), weekend/holiday moves roll into the next shared close.
Return conventions: Volatility/Sharpe/Sortino use simple daily returns. Tail-risk uses daily log returns for distribution stats (but tables show simple returns). Log returns.

Formulas

Daily simple return

r_t = \frac{P_t}{P_{t-1}} - 1

Volatility

\sigma_{ann} = \sigma(r_t)\sqrt{A}

Volatility drag (approx.)

\text{drag} \approx \tfrac{1}{2}\sigma_{ann}^2

Sharpe Ratio

S = \frac{A\,\bar{r} - r_f}{\sigma(r_t)\sqrt{A}}

Sortino Ratio

So = \frac{A\,\bar{r} - r_f}{\sqrt{\mathbb{E}[\min(0,\,r_t - r_f/A)^2]}\,\sqrt{A}}

Maximum Drawdown

MDD = \min_t\left(\frac{P_t}{\max_{s \le t} P_s} - 1\right)

Average Correlation

\rho = \frac{\operatorname{cov}(r^A,\,r^B)}{\sigma_A\,\sigma_B}

Log returns

\ell_t = \ln\left(\frac{P_t}{P_{t-1}}\right)

Notation

$P_t$: Price on day t.
$r_t$: Simple daily return.
$\ell_t$: Log daily return.
$\bar{r}$: Average daily return.
$\sigma(r_t)$: Standard deviation of daily returns.
$A$: Annualization factor (days/year).
$r_f$: Annual risk-free rate.

Sandisk vs Seagate Technology Holdings plc: Frequently Asked Questions

Which has higher volatility: SNDK or STX?

SNDK showed higher volatility at 98.0% annualized, compared to 62.1% for STX Over the past year. Higher volatility means larger price swings in both directions.

Does SNDK provide diversification when held with STX?

SNDK and STX are moderately correlated over the past year, with an average correlation of 0.54. This offers some diversification benefit, though they still tend to move together during major market moves.

How bad are the worst 5% days for SNDK vs STX?

Over the past year, SNDK's 5% VaR was -6.37% and its 5% Expected Shortfall was -13.96% (worst 13 days). STX's were -6.16% and -8.02% (worst 13 days).

Do SNDK and STX crash together on bad days?

On shared dates (n=249), when STX has a 2σ down day, SNDK also does 50.0% (3/6 days). In the other direction, when SNDK has one, STX also does 42.9% (3/7 days).

Which has better risk-adjusted returns: SNDK or STX?

SNDK showed better risk-adjusted performance with a Sharpe ratio of 3.18 versus STX's 2.61 Over the past year.

Can SNDK and STX be combined in a portfolio?

Yes, though allocation sizing matters. Their moderate correlation offers some diversification benefits. SNDK's higher volatility (98.0%) means even small allocations can materially impact overall portfolio risk.