I recently came across a financial research paper that I felt was worth sharing — not because its conclusion is comforting, but because it is not. It quietly documents something most of us sense but rarely see proven: that in a market bubble, the losses of the many become the gains of the few. What follows is my attempt to make its findings accessible to more readers.
How a Bubble Quietly Moved Money from the Many to the Few
Based on "Wealth Redistribution in Bubbles and
Crashes" by Li An (Tsinghua PBC), Dong Lou (LSE), and Donghui Shi (Fudan),
published in the Journal of Monetary Economics, vol. 126 (2022), pp. 134–153.
A Rollercoaster With a
Hidden Toll Booth
Between July
2014 and June 2015, the Shanghai Composite Index climbed more than 150%. By the
end of December 2015, it had crashed 40% from its peak. Most people remember
this episode as a wild ride that ended roughly where it started.
But three
researchers got access to something extraordinary: the Shanghai Stock
Exchange’s regulatory bookkeeping data — the daily holdings and trades of all
~40 million accounts in the market. Not a survey. Not a sample. Everyone.
What they found
should be required reading for every retail investor.
The Numbers That Should
Keep You Up at Night
The researchers
sorted all household accounts into four wealth groups by account value, with
cutoffs at 500K, 3M, and 10M RMB. The bottom group holds 85% of all accounts;
the top group is the wealthiest 0.5%. Remarkably, despite that huge difference
in headcount, the two groups started with roughly the same total wealth in the
market — which makes the comparison between them clean. Then the researchers
watched what each group did, day by day, through the entire boom and bust.
The pattern was
almost embarrassingly clean:
During the
boom, the wealthiest group (accounts above 10M RMB — the top 0.5%) poured
money in early and aggressively. By the market peak on June 12, 2015, their
cumulative adjusted inflows reached 406 billion RMB. The bottom 85% were
actually net sellers during the rise — their adjusted outflows reached
460 billion RMB by the peak.
After the peak, the roles reversed with brutal speed. In the ten weeks it took the index to fall from 5,166 to 2,927, the wealthiest group pulled 365 billion RMB out of high-beta positions. Who bought their shares? The bottom 85%, who piled in during the crash — adding 257 billion RMB of adjusted inflows after the peak.
The bill:
over the full 18 months, the bottom 85% of households lost 252 billion RMB
from their active trading, while the top 0.5% gained 252 billion RMB.
Measured against what each side started with, the poor lost about 28% of
their initial equity wealth, and the ultra-wealthy gained about 31%
— roughly 30% either way.
Same market.
Same 18 months. Same information officially available to everyone. Opposite
outcomes.
Where Did the Losses
Actually Come From?
The researchers
decomposed the transfer into two channels, each responsible for roughly half:
1. Market
timing (when to be in the market). The wealthy entered early in the bubble
and exited shortly after the peak. The poor entered late and — devastatingly —
kept buying through the crash.
2. Stock
selection (which stocks to hold). During the boom, the wealthy tilted
toward high-beta stocks — shares that amplify market moves — and rode the
updraft harder. After the peak, they rotated out of high-beta names while
smaller investors rotated into them, absorbing the steepest part of the
fall.
And here is the
detail that elevates this from anecdote to indictment: the researchers ran
forecasting regressions and found that trades by the poor negatively
predicted future stock returns, while trades by the ultra-wealthy positively
predicted them. A one-standard-deviation increase in weekly buying by the
top group predicted a 0.44% higher return the next week; the same buying
by the bottom group predicted a 0.48% lower return — a gap of 0.93% per
week that is both large and statistically overwhelming. The poor weren’t just
unlucky. Their trades were systematically pointed the wrong way.
One more
finding deserves emphasis: the skill gap is not constant — it widens with
turbulence. That 0.93% weekly return gap between the top and bottom groups
during the bubble-crash was nearly five times the 0.19% gap the same
investors showed in the calm years of 2012–2014. The authors ran the whole
study again on that calm period as a control, and the wealth transfer there was
an order of magnitude smaller. Volatility is not neutral. It is the
amplifier through which skill differences become wealth differences.
The Authors’ Verdict: It’s Skill, Not Luck
Could this be
innocent? The researchers tested the polite explanations:
●
Rebalancing needs? Their model shows
rebalancing-motivated trades explain less than 20% of even the market-timing
half of the transfer.
●
Changing risk appetites? There’s no plausible reason
risk aversion should gyrate in exactly the pattern required.
●
Trend-chasing that happened to work? The
regressions show no clear trend-chasing by the wealthy at all.
What remains,
in the authors’ words, is heterogeneity in investment skills — the ultra-wealthy
have better access to information on both aggregate market movements and
individual stocks. And crucially, this advantage is amplified in
bubble-crash episodes, precisely when volatility and trading volume peak.
In plain
language: bubbles are when the skilled harvest the unskilled.
What the Paper Doesn’t Say
Here the paper
stops — almost. The authors document the transfer and identify the cause, but
offer the ordinary investor no remedy. They do draw one broader implication.
Bubbles and crashes are as old as markets themselves — from Dutch tulip mania
to the South Sea Bubble to 1929 to the dot-com bust — and this quiet transfer
from the unskilled to the skilled is a recurring feature of all of them, rich
world and poor alike. The authors add one sobering note: because so many people
enter the market for the very first time during these bubble episodes,
the damage can be especially lasting where stock-market participation is still
young and first-time investors are the majority. Their one policy caution
follows from this: passive investing can help anyone, but active investing in
bubble-prone markets "may result in the exact opposite."
That is an
honest warning. But it is also a narrow one — a caution about how people
participate, not a full answer to what an ordinary investor should actually do.
The paper leaves that question open.
Where the Commentary Goes
Wrong
Into that open
question, popular commentary has rushed with a simple lesson. I first came
across this study through exactly that kind of commentary, and the takeaway was
always some version of the same thing: the little guy gets fleeced in
bubbles, so the safest move is to stay out.
I understand
the appeal of "just avoid it." But I don’t fully agree — and it’s
worth explaining why, because the flaw in that advice is the whole reason I
wanted to write this. Notice what "stay out" quietly concedes: it
tells the little guy to sit at the edge of the pool. And that is exactly where
I part ways, because sitting at the edge does not stop you from getting poorer relative
to those who swim. If the disease is a skill gap amplified by volatility, the
treatment is not abstinence. It is skill.
So What Can an Ordinary
Investor Actually Do?
First,
understand the game you’re in. The wealthy in this study didn’t beat the
poor with secret stocks. They beat them with relative thinking. Retail
investors typically ask a time-series question: "Is this stock going
up?" Skilled investors ask a cross-sectional question: "Which stocks
are positioned better than which, right now — and where do I stand relative to
everyone else holding them?" The study’s own evidence shows the wealthy’s
edge lived in the cross-section of stocks. You may never match their
information access, but you can stop playing the single-stock guessing game
entirely.
Second, refuse to supply the exit liquidity. The single most destructive behavior in the data was buying after the peak, from wealthy sellers, in high-beta stocks. If you cannot say precisely why a falling stock is cheap, "it’s much lower than before" is not analysis — it’s the exact reasoning that cost the bottom 85% some 252 billion RMB.
Third, make
volatility your tripwire, not your temptation. The transfer concentrated in
the most volatile stretch of the episode — the skill gap between top and bottom
investors was nearly five times wider in the bubble than in calm years. When
markets get wild and everyone around you is opening accounts, that is when the
gap costs you the most. Calm markets forgive amateurs; volatile markets bill
them.
Fourth,
automate what you cannot discipline. The wealthy’s timing looks like skill,
but you don’t need timing skill if you remove timing from your process: fixed
periodic investment into broad, low-cost index funds; a written allocation you
rebalance on a calendar, not on emotion; position sizes small enough that no
single crash forces your hand. A rules-based process is the retail investor’s
substitute for the information advantage you’ll never have.
Fifth, treat
leverage as the amplifier of your side of the skill gap. This bubble was
famously fueled by margin trading. Leverage doesn’t just amplify returns — it
amplifies whatever skill differential exists between you and your counterparty.
If the data says your trades predict returns negatively, leverage means
losing faster.
The Real Lesson
Markets do not
merely reflect wealth inequality. In their most dramatic moments, they manufacture
it — quietly, legally, and at scale. Over 18 months, one bubble moved roughly
250 billion RMB from those who could least afford it to those who needed it
least, and the mechanism was nothing more exotic than a difference in skill,
multiplied by volatility.
But the
conclusion is not to flee the market. Fleeing only guarantees that the harvest
continues without you — and the gap widens either way. The conclusion is that skill
was the weapon, and skill is not hereditary. The wealthy prepared before
they participated; most retail investors participated before they prepared.
That ordering — not income, not connections — was the difference the data
measured.
No one can, or will,
hand you a twelve-month curriculum or a step-by-step system. The way cannot be
given; it can only be taken — by those with the desire to go and seek it. The path back across this
skill gap runs through a wide range of subjects and demands a mentality of
steel, and no article can walk it for you. What an article can do is
what this one has tried to do: turn on a light, and point at the door.
The rest is
yours. And the encouraging truth — across both the traditions I was raised
between — is that the door opens for those who genuinely go looking:
"Seek, and you shall find; knock, and it
shall be opened unto you."
— Matthew 7:7
「千里之行，始於足下。」 "A journey of a thousand li begins
beneath one’s feet."
— 老子《道德經》
(Laozi, Tao Te Ching)
The next bubble
is already forming somewhere. The only question is which side of it you will be
on when it breaks — and that question is answered not on the day it breaks, but
in all the ordinary days you spend preparing before it does.
Data source: Li An, Dong Lou, and Donghui Shi, "Wealth
Redistribution in Bubbles and Crashes," Journal of Monetary Economics,
vol. 126 (2022), pp. 134–153. All figures cited are from the paper’s Tables 2,
3, and 5. (An earlier 2019 working-paper draft used slightly different group
definitions and figures; this post follows the published version.)
For those who want to read the original paper:
For those readers who want to read the original paper:
The authors' own copy on Dong Lou's LSE page — this is the exact published version
I pulled all the updated numbers from: https://personal.lse.ac.uk/loud/AnLouShi.pdf
Other access points:
·
SSRN (abstract + download): https://ssrn.com/abstract=3402254
·
LSE Research Online: http://eprints.lse.ac.uk/113766/
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