u/Aerhoespaceengineer

Follow-up from my airline seasonality post. u/KibbledJiveElkZoo asked me to test whether gold actually protects you when stocks crash. So I tested it across every major market crash since 2005.

what I did

took every major SPY drawdown since 2005 and checked what gold did over the same period, peak to trough. simple question: when stocks are dying, does gold save you?

data: GLD (gold), SPY (S&P 500), TLT (20yr treasury). all via yfinance.

results

Crisis	Stocks (SPY)	Gold (GLD)	Treasuries (TLT)
GFC (2007-09)	-55.2%	+23.9%	+25.1%
Debt ceiling (2011)	-18.6%	+5.6%	+34.6%
China/oil (2015-16)	-13.0%	+2.9%	+13.2%
Q4 selloff (2018)	-19.3%	+5.0%	+4.5%
COVID crash (2020)	-33.7%	-3.6%	+14.2%
2022 bear market	-24.1%	-8.8%	-31.2%
Tariff shock (2025)	-18.8%	+1.6%	+0.8%

gold beat stocks in 7 out of 7 crashes. that's pretty convincing

but it's not that simple

gold went negative in 2 of those 7 crises. during covid it got sold along with everything else because funds needed cash. in 2022 rising rates crushed it because gold pays no yield

also tested what gold does on SPY's single worst days (every day SPY dropped 2%+ over 20 years). gold was basically flat. not a same-day hedge at all. treasuries were way better for that

so is gold a safe haven?

* for slow crises and long drawdowns: yes, pretty clearly

* for fast panics where everyone sells everything for cash: no

* for daily hedging: no

u/KibbledJiveElkZoo you had it right, gold is probably only a true safe haven in crises bigger and slower than what we normally experience. the GFC was its best moment. covid was its worst

what should I test next?

code and methodology: github.com/jsabazova/hunchtest

Source: Yahoo Finance via yfinance. Tool: Python (pandas, scipy, matplotlib).

not financial advice. I just like arguing with conventional wisdom using data

People say buy airlines before summer like its some obvious play. more people fly, airlines profit, stock goes up. right?

I actually tested this properly instead of just vibing about it

what I did

ran an event study (same methodology from academic finance) on 5 US airlines Delta, United, Southwest, American, JetBlue across 10 years (2015-2025, minus 2020 because covid breaks everything)

looked at the 20 trading days before June 1 each year and measured how much each stock moved vs what the S&P 500 would predict. so you're only seeing the airline-specific move, not just "the market went up"

market model is basic CAPM. fit a regression on 60 days of data before the window, then measure abnormal returns during the window. cumulative abnormal return (CAR) = the total excess move

results

the basket averaged -1.09% over the pre-summer window. lol

by airline:

• DAL: +0.30% (p=0.92)
• UAL: -0.54% (p=0.85)
• AAL: -0.86% (p=0.84)
• LUV: -1.97% (p=0.32)
• JBLU: -2.38% (p=0.24)

nothing is significant. 4 out of 5 airlines actually went DOWN relative to the market before summer. basket only had a positive CAR in 3 out of 10 years

2025 was a massive outlier at +12.5% which pulled the average up. without that its even worse

why this probably doesn't work

if summer seasonality was real and predictable, sell-side desks would have priced it in decades ago. also airlines are way more sensitive to fuel prices, rates, and macro than seasonal booking patterns. the CAPM strips out broad market moves but sector shocks still contaminate

also 10 years excluding covid is not a huge sample. you'd need a really strong effect to clear significance with that

what should I test next?

thinking about:

• do retail stocks actually pump before black friday
• do apple shares move after keynote events
• oil stocks around OPEC meetings
• does the pattern change if you split by years where fuel prices were falling vs rising

what theories do you want tested? the weirder the better

code is on github if anyone wants to check my work or run their own: github.com/jsabazova/hunchtest

not financial advice, past performance doesn't guarantee future results, I just like running regressions on things that don't matter

People says buy airlines before summer because more people fly, airlines profit, stock goes up. right? I actually tested this properly instead of just vibing about it

what I did

ran an event study (same methodology from academic finance) on 5 US airlines Delta, United, Southwest, American, JetBlue across 10 years (2015-2025, minus 2020 because covid breaks everything)

looked at the 20 trading days before June 1 each year and measured how much each stock moved vs what the S&P 500 would predict. so you're only seeing the airline-specific move, not just "the market went up"

market model is basic CAPM. fit a regression on 60 days of data before the window, then measure abnormal returns during the window. cumulative abnormal return (CAR) = the total excess move

results

the basket averaged -1.09% over the pre-summer window. lol

by airline:

• DAL: +0.30% (p=0.92)
• UAL: -0.54% (p=0.85)
• AAL: -0.86% (p=0.84)
• LUV: -1.97% (p=0.32)
• JBLU: -2.38% (p=0.24)

nothing is significant. 4 out of 5 airlines actually went DOWN relative to the market before summer. basket only had a positive CAR in 3 out of 10 years

2025 was a massive outlier at +12.5% which pulled the average up. without that its even worse

why this probably doesn't work

if summer seasonality was real and predictable, sell-side desks would have priced it in decades ago. also airlines are way more sensitive to fuel prices, rates, and macro than seasonal booking patterns. the CAPM strips out broad market moves but sector shocks still contaminate

also 10 years excluding covid is not a huge sample. you'd need a really strong effect to clear significance with that

what should I test next?

thinking about:

• do retail stocks actually pump before black friday
• do apple shares move after keynote events
• oil stocks around OPEC meetings
• does the pattern change if you split by years where fuel prices were falling vs rising

what theories do you want tested? the weirder the better

code is on github if anyone wants to check my work or run their own: github.com/jsabazova/hunchtest

not financial advice, past performance doesn't guarantee future results, I just like running regressions on things that don't matter