Radio 4 sent me to New York to find out The Truth About Goldman Sachs. And I can exclusively reveal the shock answer: it is beige.

The New York-based investment bank (more on what that means later) has moved into a brand new Global Headquarters right by the square where the twin towers once stood. One of the world's most profitable ($13.4 billion after tax in 2009) and successful banks, it owns and designed the new building - though $200 million came from US taxpayers. But if you expect ostentation comparable to the triple, storey-high neon signs which once circulated the name Lehmann Brothers round that now bankrupt company's Times Square headquarters, you will be disappointed.

No name. No logo. Just the address, 200 West Street, cut out of the plain grey stone portico above its doors. At an almost intimidating distance across the large entrance lobby sit three identically clad receptionists. To their left droop the flags of the United States and New York. But on the acres of plain beige stone wall behind them there is nothing even to hint who might occupy 200 West Street. Nor anywhere in the vast triple height lobby clad in plain beige stone and floored with large square charcoal grey tiles. One insider told me that the décor, which is the same throughout, was 'tasteful but understated'. Then insisted in an understated but tasteful way that this revelation was off the record.

I travelled up to the 11th floor Sky Lobby, where more plain beige stone looked down on workers rushing with their lunch from the canteen back to their desks. This large interchange gives access to the upper floors so I headed for Floor 42 and Meeting Room J to wait for the Partner I would interview and admired the view over the Hudson River to Goldman's other 42 storey tower dominating the opposite shore. Finally I spotted the Goldman Sachs branding - a plain blue grey square with the name picked out in white. On a pencil. Left on the table should I wish to make notes and had forgotten my own. I didn't. I hadn't. But I kept the pencil.

And investment banks? They buy stuff. They sell stuff. Sometimes their own stuff. Sometimes for other people (but don't turn up unless you have at least $25 million). So why do so many hate Goldman Sachs with such a passion? And why has the US regulator, the Securities and Exchange Commission (think the Financial Services Authority on steroids, with attitude, and armed) filed charges of securities fraud against the bank?

Is it because as well as buying and selling stuff Goldman Sachs also buys and sells bets on whether the stuff it buys and sells will go up or down in value? And buys and sells insurance against losing money on those bets. And places bets itself that stuff it sells to clients will go down when its clients hope it will go up. Is that it? Probably not. Goldman Sachs has always done that. And in any case it isn't gambling, the Partner tells me, it is allocating capital and, she insists, investment.

Or is it because almost half of its vast profits are divvied out among the staff? In the past fifteen percent of the fund - which in 2009 was $16.2 billion - has gone to the 400 or so partners (do the math, as they say here). Much of the rest goes to the 'revenue generators' (principally the ones who buy and sell all that stuff) and the balance to the 'Federation' of support and administrative staff.

It is this remuneration - which the bank prefers to call 'compensation' rather than 'pay' - which strikes at the heart of Middle America where average household income is $50,303 a year and falling. Each partner in the US got millions of dollars in 2009 on top of their $600,000 pay. And of course most people outside the banking world do not understand what that job is. Or what its purpose is.

That may not be the truth about Goldman Sachs. But is it a truth. And one it has yet to deal with.

Paul Lewis is presenter of Money Box, Money Box Live and The Truth About Goldman Sachs

• The Truth About Goldman Sachs is on Radio 4 tonight at 2000 and on the iPlayer for seven days.
• Edward Stourton profiled Lloyd Blankfein, CEO of Goldman Sachs on Radio 4's Profile in April.
• The picture shows the pencil Paul picked up in that Goldman conference room. There are more pictures here.

http://www.bbc.co.uk/programmes/b00n58kf

I ask because Money Box Live will be live from Glasgow on Wednesday October 14 as part of the BBC's Money Matters Roadshow. The programme will be taking questions live from an audience at the Buchanan Galleries shopping centre on savings, investments and pensions.

Last time we did this - in Manchester in February - I was really pleased to meet the people asking the questions, and dozens more around the show throughout the day, to talk money. Hundreds of people were helped throughout the day. The queues for advice on saving, investment, and pension planning were by far the longest. So this time we have decided to take those as our topics for Money Box Live.

I would like to hear in advance what you - Radio 4 blog readers - would like to ask about cash savings, investing a bit of money, or putting hard-earned wages into a pension. I can't promise we will answer your specific query. But I will make sure that the main subject areas you raise are covered one way or another. Click here to let me know.

The Money Matters Roadshow will be open all day from 8am to 6.30pm at the Buchanan Galleries. So if you happen to be in Glasgow on Wednesday 14 October why not come along for free money advice?

There will be 30 financial experts offering confidential help to all comers and you will see some of the BBC's top financial journalists. Plus you can join the audience and watch Money Box Live go out live - and see what we all look like! You might even get your question answered live on air.

Money Box Live from Glasgow is broadcast live on Wednesday 14 October at 3pm on Radio 4. And there will be an extra half hour of questions and answers published on our website later.

I would love to see you there!

Paul Lewis is presenter of Money Box and Money Box Live

• The picture is by Jason Rogers and is used under licence.