What has Goldman Sachs been doing since 2008? A simple question with a complex answer.
The BBC programme Assignment has been looking for it.
More specifically - how has Goldman Sachs made so much money since the credit crisis of 2008?
The answer: Goldman has become a half-and-half bank - part investment, part ordinary.
It still acts as an investment bank, but one with government protection and cheap Fed loans like a High Street bank.
And it's still making billions of dollars of profits from the very financial instruments which caused the crisis. over-the-counter derivatives.
Against a backdrop of fraud charges, hostile Senate hearings, and congressional battles over regulatory reform, Wall Street's pre-eminent bank has been fighting for its reputation and its share price.
A senior advisor to Goldman, Arthur Levitt, told us Goldman staff feel "scapegoated" and that Congress "is taking cheap shots, using vulgarity, and trivialising a company which has performed so admirably throughout the years".
So, is Goldman Sachs being picked on? Yes, and rightly so, says journalist Matt Taibbi, who wrote a blistering polemic against the firm in Rolling Stone magazine, in which he likened Goldman to "a vampire squid wrapped round the face of humanity".
"People like me have decided to make a symbol out of them for the excesses of Wall Street," he says.
"They can't have it both ways - they can't claim to be the kings of Wall Street one day and then claim to be unfairly victimised the next day."
And recently there have been street protests across the US calling for bank reform.
Last week several thousand people took part in what was billed as a march by Main Street on Wall Street.
Eighteen months on from the worst of financial crisis people are still angry.
As they marched through the financial heart of America they chanted "They got bailed out, we got sold out" and "Hey, hey Goldman Sachs, time to give our money back."
Goldman Sachs recently revealed that seven lawsuits have been issued against it by shareholders.
One securities fraud lawyer we spoke to, Tom Ajamie, employed a team of legal experts to explore Goldman's current derivatives deals but could find very little information on what its traders do.
"My fear is that Goldman Sachs is a black box company, and black box companies make me nervous," he says.
Goldman's public persona is anything but that of a black box company.
It privatises state industries, advises governments, floats companies, restructures debt for entire nations - all things investment banks traditionally do.
But on Wall Street it's seen as a traders' firm.
And that has fuelled accusations that there are too many conflicts of interest - at worse that Goldman uses its clients to inform its own trades, even if that costs clients money.
The bank has come out fighting.
Arthur Levitt says that current congressional proposals to beef up Wall Street regulation will "satisfy the public which is lusting for revenge but will do nothing to prevent another meltdown of the kind that we have seen".
He says the bank supports reform, the regulation of derivatives, but not a publicly scrutinised exchange for all derivatives.
"Certain customized derivatives have virtually no trading, no open interest, and to force them onto an exchange or clearing house really would not be at all constructive," he says.
But those "customized derivatives", tailor-made for a handful of the wealthiest clients, both precipitated the financial crisis and remain the most lucrative deals for banks like Goldman Sachs.
Opaque, complex, and private.
On Friday, Goldman Sachs executives will come face to face with shareholders at their annual general meeting.
They have made their investors a lot of money. But will they be thanked?
Assignment will first be broadcast in Europe at 0906 GMT/1006 BST on Thursday 6 May, 2010. It can also be accessed online through www.bbcworldservice.com/programmes