[JumpCrisscross]

> Whatever model you run is most probably wrong because jumbo loans are not priced double and actually are priced pretty close to the conforming loans

Modelling non-jumbo loans provided without support. I have a jumbo mortgage. I also had substantial assets when I took it out, substantial income and opted to put 25% down. Remove those factors and your credit component starts interacting with duration in complex ways.

Remove that part of the market--the massive number of guaranteed, conforming mortgages--and the securitisation and hedging infrastructure that supports jumbo fixed 30-year loans falls apart [1].

[1] https://www.tandfonline.com/doi/full/10.1080/15214842.2020.1...

[pandaman]

It's great that you have substantial assets but neither that, nor the article "model" anything. Also you are now changing your argument from "remove F&F" to "remove securitization and hedging infrastructure". As I already pointed out, if F&F did not exist, another firm could have done exactly the same securitization, as many do on non-government controlled markets right now.

[JumpCrisscross]

> neither that, nor the article "model" anything

I was showing why 30y-fixed jumbos exist as a result of F&F. You argued an incorrect connection between jumbos within the current system as a proxy for unsubsidised mortgages in a non-F&F system.

> if F&F did not exist, another firm could have done exactly the same securitization, as many do on non-government controlled markets right now

Show me a single one that does for fixed-rate 30-year mortgages to average Americans at scale. Or a single other country that does this.

F&F can do that at the scale they do because they have an implicit guarantee. That creates securitisation and hedging infrastructure for that product that niche firms, like those doing jumbos, can piggyback on. Take out F&F and there isn’t the mass market which means you lose the product. (And no, another firm can’t trivially mint an implicit guarantee from the U.S. government.) Going back to the original point of this thread: they’re far more critical to this process than the Fed.

Genuine question: have you or someone you know traded mortgages?

[pandaman]

>I was showing why 30y-fixed jumbos exist as a result of F&F. You argued

I understood that. But showing that something is a result of something else needs some kind of logic, stating both things exist does not establish a casual relationship. You can try it for yourself by applying your own argument in the reverse direction: if your logic had been sound then it would also be true that F&F exist because of 30 years fixed jumbo loans.

>F&F can do that at the scale they do because they have an implicit guarantee. That creates securitisation

What? Securitization is turning something into securities, it's a process that is not caused by any guarantees, you can do it yourself.