ACHR vs JOBY: Stock Returns, Risk & Volatility (2026)

Q: Which is a better investment: ACHR or JOBY?

Over the past year, JOBY looks like the better investment: it had higher total return (JOBY +38.5% vs ACHR -25.5%) and a higher Sharpe ratio (JOBY 0.75 vs ACHR -0.06). On risk, ACHR was less volatile (ACHR 77.4% vs JOBY 80.7%), JOBY had a smaller max drawdown (JOBY -61.1% vs ACHR -63.8%), and JOBY had less severe losses on the worst 5% of days (Expected Shortfall of JOBY -9.30% vs ACHR -10.06%).

Written by Gale Finance Team

Reviewed by Sid Kalla CFA Charterholder

Quick answer

Which is a better investment: ACHR or JOBY?

Over the past year, JOBY outperformed (-25.5% vs +38.5%) with a Sharpe ratio of 0.75.

Total Return

ACHR -25.5%

JOBY WIN +38.5%

Sharpe Ratio

ACHR -0.06

JOBY WIN 0.75

Annualized Volatility

ACHR WIN 77.4%

JOBY 80.7%

Max Drawdown

ACHR -63.8%

JOBY WIN -61.1%

Analysis period: 2025-04-14 to 2026-04-10

ACHR Total Return

↓ -25.5%

JOBY Total Return

↑ +38.5%

Relative Performance of ACHR vs JOBY (Normalized to 100)

ACHR JOBY

Normalized to 100 at start date for comparison

Key Takeaways

Total Return: ACHR delivered a -25.5% total return, while JOBY returned +38.5% over the same period. JOBY outperformed on total returns.
Risk-Adjusted Return (Sharpe Ratio): ACHR had a negative Sharpe (-0.06) while JOBY was positive (0.75), indicating JOBY had meaningfully better risk-adjusted performance in this period.
Volatility (Annualized): JOBY was more volatile, with 80.7% annualized volatility, versus 77.4% for ACHR.
Maximum Drawdown: JOBY's maximum drawdown was -61.1%, while ACHR experienced a deeper drawdown of -63.8%.
Tail Risk (VaR & Expected Shortfall): At the 5% level (daily log returns), ACHR's VaR was -7.62% and its Expected Shortfall (CVaR) was -10.06%; JOBY's were -6.88% and -9.30%. VaR is the cutoff; Expected Shortfall is the average move on the worst days.
Skew & Kurtosis: Skew: ACHR 0.30 vs JOBY 0.79. Excess kurtosis: ACHR 1.77 vs JOBY 3.29. Negative skew leans downside; higher excess kurtosis means fatter tails.
Tail Days & Extremes: 2σ tail days (down/up): ACHR 4/6, JOBY 2/10. Worst day: ACHR -14.83% (2025-06-13) vs JOBY -16.68% (2026-01-29). Best day: ACHR +22.91% (2025-05-13) vs JOBY +28.78% (2025-05-28).
Risk ratios: Sortino - ACHR: -0.09 vs. JOBY: 1.26 , Calmar - ACHR: -0.40 vs. JOBY: 0.64 , Sterling - ACHR: -0.68 vs. JOBY: 1.42 , Treynor - ACHR: -0.02 vs. JOBY: 0.24 , Ulcer Index - ACHR: 34.87% vs. JOBY: 30.21%

Archer Aviation vs Joby Aviation Correlation

0.74 Average Correlation

Archer Aviation and Joby Aviation are strongly correlated over the past year. With a correlation of 0.74, these assets tend to move together, limiting diversification benefits.

For portfolio construction, this strong correlation means holding both ACHR and JOBY provides limited risk reduction — they're likely to decline together in downturns.

Metric	Value
Current (30-day)	0.90
Average (full period)	0.74
Minimum	0.33
Maximum	0.92

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 April 14, 2025:

ACHR $7,448.28 -25.5%

JOBY $13,853.82 +38.5%

Difference: $6,405.54 (JOBY ahead)

Archer Aviation and Joby Aviation: Risk Analysis

Archer Aviation experienced its maximum drawdown of -63.8% from 2025-10-06 to 2026-03-30. It has not yet recovered to its previous peak.

Joby Aviation experienced its maximum drawdown of -61.1% from 2025-08-04 to 2026-03-30. It has not yet recovered to its previous peak.

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

Sharpe Ratio of ACHR and JOBY

ACHR Sharpe Ratio

↓ -0.06

JOBY Sharpe Ratio

↑ 0.75

Sharpe ratio measures return per unit of risk (volatility). A higher Sharpe indicates better risk-adjusted performance. ACHR had a negative Sharpe (-0.06) while JOBY was positive (0.75), indicating JOBY had meaningfully better risk-adjusted performance in this period.

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 ACHR and JOBY

ACHR Sortino Ratio

↓ -0.09

JOBY Sortino Ratio

↑ 1.26

Sortino ratio measures return per unit of downside risk. Unlike Sharpe, it only counts downside deviation (returns below the target return). JOBY 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: ACHR 51.5% vs JOBY 47.9%. 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 ACHR and JOBY

ACHR Calmar Ratio

↓ -0.40

JOBY Calmar Ratio

↑ 0.64

Calmar ratio compares CAGR to maximum drawdown. Higher Calmar means more return per unit of worst drawdown. JOBY 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 ACHR and JOBY

ACHR Sterling Ratio

↓ -0.68

JOBY Sterling Ratio

↑ 1.42

Sterling ratio measures excess return per unit of average drawdown (typically drawdowns worse than 10%). JOBY 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 ACHR and JOBY

ACHR Treynor Ratio

↓ -0.02

JOBY Treynor Ratio

↑ 0.24

Treynor ratio measures excess return per unit of market risk (beta) instead of total volatility. JOBY 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 ACHR and JOBY

ACHR Ulcer Index

34.87%

JOBY Ulcer Index

30.21%

Ulcer Index captures drawdown depth and duration. Lower Ulcer Index means less drawdown pain. JOBY 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): Archer Aviation vs. Joby Aviation

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)	ACHR	JOBY
5% VaR (daily log return)	-7.62%	-6.88%
5% Expected Shortfall (CVaR)	-10.06% (worst 13 days)	-9.30% (worst 13 days)
Skew	0.30	0.79
Excess kurtosis	1.77	3.29
2σ tail days (down / up)	4 / 6	2 / 10
Worst day	-14.83% (2025-06-13)	-16.68% (2026-01-29)
Best day	+22.91% (2025-05-13)	+28.78% (2025-05-28)

Downside co-moves (2σ) — 1-Year

Computed on shared dates only (n=248). 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 JOBY has a big down day, ACHR also does

0.0%

0 / 2 days

When ACHR has a big down day, JOBY also does

0.0%

0 / 4 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 ACHR and JOBY had a big down day (2σ)

None in this window.

Days when ACHR had a big down day

Date (interval)	ACHR	JOBY
2025-05-16 → 2025-05-19	-14.36%	-4.87%
2025-06-13	-14.83%	-3.04%
2025-07-18 → 2025-07-21	-10.84%	-5.29%
2026-03-03	-10.64%	-4.97%

Days when JOBY had a big down day

Date (interval)	ACHR	JOBY
2025-11-04	-8.25%	-9.56%
2026-01-29	-3.88%	-16.68%

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.

Archer Aviation vs Joby Aviation Volatility (ACHR vs JOBY)

ACHR Volatility

77.4%

±4.88% daily

JOBY Volatility

80.7%

±5.08% daily

Typical daily swing

ACHR

±4.88%

JOBY

±5.08%

Archer Aviation's annualized volatility of 77.4% means it typically moves ±4.88% on any given day.

Joby Aviation's annualized volatility of 80.7% means it typically moves ±5.08% on any given day.

JOBY's higher volatility means a wider path to returns — this can be attractive for tactical, shorter-term exposure, while ACHR'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.

Archer Aviation vs Joby Aviation Performance Over Time

Metric	ACHR	JOBY
30 Days	-16%	-18.5%
90 Days	-38.7%	-45.8%
180 Days	-54.9%	-48.8%
1 Year	-25.5%	38.5%

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

Full Comparison of Archer Aviation vs. Joby Aviation (1-Year)

Metric	ACHR	JOBY
Total Return	-25.5%	+38.5%
Annualized Volatility	77.4%	80.7%
Sharpe Ratio	-0.06	0.75
Sortino Ratio	-0.09	1.26
Calmar Ratio	-0.40	0.64
Sterling Ratio	-0.68	1.42
Treynor Ratio	-0.02	0.24
Ulcer Index	34.87%	30.21%
Max Drawdown	-63.8%	-61.1%
Avg Correlation to S&P 500	0.49	0.45
5% VaR (daily log return)	-7.62%	-6.88%
5% Expected Shortfall (CVaR)	-10.06%	-9.30%
Skew	0.30	0.79
Excess kurtosis	1.77	3.29
2σ tail days (down / up)	4 / 6	2 / 10

Audit this calculation

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

Inputs & conventions

Shared window for pair metrics: 2025-04-14 → 2026-04-10 (last shared close).
Rolling correlation sample (shared closes): 219 rolling 30-day values (from 248 shared daily returns).
Annualization (days/year): ACHR: 252 days/year; JOBY: 252 days/year.
Risk-free rate: Uses the 3-month U.S. Treasury yield (FRED: DGS3MO), averaged over each asset’s window:

ACHR: 4.17% over 2025-04-14 → 2026-04-10.

JOBY: 4.17% over 2025-04-14 → 2026-04-10.
Volatility drag (rule of thumb): Estimated from annualized volatility (simple returns). For the log-return framing, see Log returns.

ACHR: ≈ -30.0%/yr

JOBY: ≈ -32.6%/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.

Archer Aviation vs Joby Aviation: Frequently Asked Questions

Which has higher volatility: ACHR or JOBY?

JOBY showed higher volatility at 80.7% annualized, compared to 77.4% for ACHR Over the past year. Higher volatility means larger price swings in both directions.

Does ACHR provide diversification when held with JOBY?

ACHR and JOBY are strongly correlated over the past year, with an average correlation of 0.74. This strong correlation limits diversification benefits.

How bad are the worst 5% days for ACHR vs JOBY?

Over the past year, ACHR's 5% VaR was -7.62% and its 5% Expected Shortfall was -10.06% (worst 13 days). JOBY's were -6.88% and -9.30% (worst 13 days).

Do ACHR and JOBY crash together on bad days?

On shared dates (n=248), when JOBY has a 2σ down day, ACHR also does 0.0% (0/2 days). In the other direction, when ACHR has one, JOBY also does 0.0% (0/4 days).

Which has better risk-adjusted returns: ACHR or JOBY?

ACHR had a negative Sharpe (-0.06) while JOBY was positive (0.75) Over the past year, indicating JOBY had meaningfully better risk-adjusted performance.

Can ACHR and JOBY be combined in a portfolio?

Yes, though allocation sizing matters. Their strong correlation provides limited risk reduction since they tend to move together. JOBY's higher volatility (80.7%) means even small allocations can materially impact overall portfolio risk.

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