In one sentence: Answering a listener's question about whether short selling is wrong, Phil and Danielle explain how a short sale works, how GameStop's squeeze happened, and why they conclude short sellers act like wolves for a herd, as long as regulators stop shares being shorted more than exist.
Key ideas
- Challenge your favourite idea. Munger says a year is wasted if he hasn't destroyed one of his own well-loved ideas. Ideas that harden into dogma become confirmation bias. Phil's example is an owner of Boeing explaining away an engine incident. Danielle adds that pessimism can be a bias too. [07:00–12:00]
- How a short sale works. The short seller borrows shares from a broker (who got them from an owner for a small fee), sells them, and must buy them back later. The sale proceeds sit with the broker as security. If the price falls, the seller profits, and if it rises, the loss has no ceiling. [15:00–19:00]
- The GameStop squeeze. According to the hosts, more shares had been lent and sold than existed, because the same shares were re-lent after each sale. When buyers on Reddit's Wall Street Bets bought and held, there were no sellers, so the price shot up and shorts were forced to buy back. [19:00–24:00]
- Why Robinhood limited buying. Phil's account is that clearinghouse rules required more collateral than the broker held, and the broker raised the money quickly. Limiting purchases cut the requirement. He says this was forced, not a conspiracy, though the effect protected the hedge funds. [24:00–28:00]
- More claims than things. The same pattern, more people holding a claim than the asset allows, is what hurt the system in 2008 with insurance on mortgage bonds. Phil calls it a nuclear weapon in finance. [27:00–29:30]
- Short sellers as wolves. A herd with no wolves overgrazes and starves. Short sellers, who are paid for it, find frauds and failures that regulators assume the board already checked. Danielle changes her earlier wish for a long-only market. [29:00–32:00]
- A caution about bankruptcy. Phil argues that bankruptcy courts, which prioritise jobs, can let hedge funds shorting a company take control of it. The hosts say nothing suggests that happened at GameStop. [32:00–35:00]
- A workable rule. Short selling stays, but regulators should prevent shares sold short from exceeding the shares that exist. [35:00–36:30]
- Options history. Before the 1960s, warrants (long-dated calls given as a sweetener) were the main option-like claims. Once any such claim exists, a market forms around it. Ed Thorp, who beat blackjack, worked out how to price them. [36:00–41:30]
- Start small. Thorp took $10,000 to Vegas, not $100,000, so fear of losing someone else's money wouldn't cloud his play. Danielle takes this as the right practice for a beginner. [42:00–44:00]
How it maps to RuleOne
- High short interest is a data point worth reading on /stock/TICKER/ as a prompt to look for what the sellers know. Compare with the short-seller step of the research funnel in 001.
- Starting small matches the idea of a starter position while you finish your research.
Buffett, Munger and Graham links
- Buffett (the quote in the show notes, as recalled): short sellers have often exposed frauds or semi-frauds. Check the source year before citing.
- Munger on destroying your own ideas is a staple of his talks (for example the "Worldly Wisdom" talk).
- Buffett's warnings about derivatives as "financial weapons of mass destruction" are in the 2002 Berkshire letter.
Words to know
- Short sale: selling borrowed shares in the hope of buying them back cheaper.
- Short squeeze: a rush of buying that forces short sellers to cover at higher prices.
- Warrant: a long-dated right to buy a stock at a set price.
Try this
Open a stock on /stocks/ that has fallen sharply. Write down the short seller's best case against it in three sentences, then read the latest 10-K risk factors to see which parts are real.
Check yourself
- What is a short squeeze?
Answer
Heavy buying pushes the price up, and short sellers must buy back shares at higher prices, which pushes it up further. - Why do Phil and Danielle think markets need short sellers?
Answer
They are paid to find fraud and failure, keeping prices honest, like wolves keep a herd healthy. - What rule do they suggest?
Answer
Stop more shares being sold short than exist.
Short quotes
"The same reason that wolves are very important to a caribou herd." (Phil, ~29:50, auto-transcribed)