Can I trade stocks without any broker ? How much money I need to open my own clearing firm ?

Lol, you believe in fairytales and seem to think margin is created out of thin air ...

 

No, the broker provides zero! It's just a book value. That's the whole trick in this.

 

It seems like you don't understand margin ...

Literally the first sentence on investopedia:

What is Margin?
Margin is the money borrowed from a brokerage firm to purchase an investment.

 

But we are talking of the brokerage firm itself! And not of its client!...

 

If you as your own broker want to trade with leverage you still need to borrow money, just as Lehman did.

 

Just give us an example on how you think this would work.

 

Man, I already gave you a good example here:
https://support.kraken.com/hc/en-us/articles/203053116-How-leverage-works-for-margin-trading

I can give you even a better example. Will try to find it...

 

The funny thing is you are saying you are talking about the broker itself and not his client, yet the example you show is about trading with leverage provided by the broker to its client ...

In your example Kraken is providing a loan for the margin.

 

Here, try this example for a bank or broker:
http://www.eurexwbt.de/index.php/en...in-the-daily-offsetting-of-profits-and-losses

Got it, finally?

 

Lol, and now you are comparing futures to stocks ...