Investors watching the vertigo-inducing rise—and Thursday’s fall—of technology stocks are buzzing about a single trade, a giant but shadowy bet on Silicon Valley big enough to pull the market up with it.
The investor behind that trade, according to people familiar with the matter, is Japan’s SoftBank 9984 -3.21% Group Corp., which bought options tied to billions of dollars worth of individual tech stocks. Investors and analysts, aware of the activity but in the dark as to who is behind it, say it has turbocharged the tech sector, whose sheer size drives broader market moves.
A SoftBank spokesperson declined to comment.
The stock market rebounded to record highs this year despite serious pain in the economy from the coronavirus pandemic. Tech stocks led the charge as work, school and entertainment shifted online, but entered a new phase in recent weeks.
Before this week’s retreat, Apple Inc. had gained nearly $700 billion in market value since the end of July and Tesla Inc. shares more than doubled, making the electric car maker one of world’s 10 most valuable companies.
Regulatory filings show SoftBank bought nearly $4 billion of shares in tech giants such as Amazon.com Inc., Microsoft Corp. and Netflix Inc. this spring, plus a stake in Tesla. Not included in those disclosures is the massive options trade, which is built to pay off if the stock market rises to a certain level and then lock in gains, the people said.
SoftBank spent roughly $4 billion buying call options tied to the underlying shares it bought, as well as on other names, according to a person familiar with the matter. It also sold call options at far higher prices. This allows SoftBank to profit from a near-term run-up in stocks and then reap those profits by unloading its position to willing counterparties | 
