The debacle surrounding Archegos Capital Management has caused chaos for major banks, including a $4.7 billion hit Credit Suisse announced on Tuesday.
Here is a look at some of the key questions behind Wall Street's latest financial debacle:
What is Archegos?
In ancient Greek, Archegos means "someone who leads the way," an ironic moniker given the implosion of this "family office" built on the fortune of founder Bill Hwang.
Such firms, which manage the holdings of ultra-high-net-worth investors, are much more lightly regulated than firms that manage money for the broader investor universe.
"As we have just seen, the failure of a large family office can cause significant harm to our financial markets," Dan Berkovitz, commissioner of the US Commodity Future Trading Commission, said last week.
In recent years, family offices have become more consequential, now managing some $6 trillion in assets worldwide, according to a report by management school Insead.
Who is behind the scandal?
Hwang, a 57-year-old South Korean-born investor at the center of the firestorm, has been depicted in the US financial press as a devout Christian who amassed huge wealth through risky bets built around loaned funds.
After emigrating to the United States and studying economics at the University of California, Los Angeles, Hwang made his mark under the wing of Julian Robertson, a prominent investor from hedge fund Tiger Management.
Hwang launched his own fund a few years later with help from Robertson.
What are swaps and how do they fit into this?
Archegos made heavy use of "total return swaps," derivative products that allowed its traders to bet on equities.
Archegos "paid a fee to banks" to obtain the swap and "then could keep the net profit on the stock bets," said Eric Dor, a professor at the IESEG School of Management. But Archegos was on the hook if the stock bets floundered.
Hwang's firm entered into transactions with several large banks, including Goldman Sachs, Morgan Stanley and Credit Suisse, that allowed for outsized bets with relatively little up-front cash. However, the full picture was not clear from the outside.
"Swaps are a source of opacity to the broader market," Dor said. "They can be used to hide a firm's total exposure."
"If each bank had known Archegos was doing the same with other banks, no one would have done it," Andrew Beer, managing partner of Dynamic Bet Investments, told AFP.
What are 'margin calls'?
A "margin call" takes place after the financial intermediaries -- in this instance large banks -- demands extra cash to cover losses in an account.
In Archegos' case, the firm became suddenly exposed following a big drop in ViacomCBS shares in late March.
"One a stock goes down and Archegos cannot cover the margin call, cannot cover the future losses, it becomes" the bank's problem, Beer said.
Once a bank finds itself in a scenario where a client cannot pay a margin call, the bank can either sell off Archegos' underlying investments to cover the money owed, or manage the underlying investment and attempt to minimize losses.
Who got hit hardest?
Some banks responded more quickly than others in the eventual liquidation, which The Wall Street Journal dubbed a "fire sale."
While Goldman Sachs and Morgan Stanley had inconsequential losses, Credit Suisse Tuesday disclosed deep losses that prompted executive departures and a cut in its dividend.
Mizuho could suffer $90 million in losses connected to Archegos, according to the Japanese press. Japanese firms Nomura and Mitsubishi UFJ have also been hit by the debacle.