Hi, very interesting tool. Thanks for sharing. While playing with it, I see some weights that are confusing. In some portfolios I see weights that are > 1 as well as some that are -ve (and I have long only portfolios) - so not sure how to interpret this (does >1 mean use leverage? I haven't read the blogs in detail yet, but are these portfolio weights static (ie equivalent to buy and hold in these ratios)? Is there anything like recomputing weights periodically and rebalancing the portfolio?

So the negative weights are just ignored during the forward and back tests. They are there just to show you the raw portfolios without any filtering.

As for the other question, the weights are just proportions of your money that you should put in each stock. If a weight is negative, that means just short with that proportion. You can simply normalize the weights to sum up to one if it's harder to read them without them being normalized.

Let me know if you have any other questions. Happy to answer.

Does this interest rate transfer to lower mortgage rates? Is now a good time to refinance loans?

Just apply and see what rate they give you. The initial applications are annoying but once you've done that you can drag your application with a lender out for a long time so long as they can still mark it as an "active" file.

I worked in the industry and your credit score was the primary reason we based off your rate, and we knocked it down a bit if there was a promo or if you had autopay.

You don't get dinged hard by just applying. Ask how long they keep your credit report before pulling it again and just get rate quotes during that time period. It's smart and also lenders know when they'll be increasing rates before it goes in affect so it doesn't hurt to do it now and then just wade it out.

Also ask for a rate modification. Nobody knows about this but you can request to get just your rate modified and nothing else changes. It's WAY less time consuming, cheaper, you don't need an appraisal, and can be done in a day. The downside is you can't get "new money" (more than your current principle balance) and you're not extending your loan.

It will, but not just yet. There’s too many people trying to refi right now and supply can’t keep up with demand, so rates are higher than they should be. Give it another 3-6 months and I wouldn’t be surprised if mortgage rates fell by another 1%.

There must be some floor based on default rates right? If 2% of people default you can't go below 2%. And of course default rates go up in recessions.

I personally don’t think there’s a floor, all that matters is spread over treasuries. If we go with your 2% number, that’s the spread between the mortgage risk and the risk-free rate. If risk-free goes to -1%, then it’d make sense for mortgages to go to 1%. This is something that already happens in European countries. I don’t think there’s an inherent reason for the risk-free rate to be a positive number.

On a different note, 2% default != 2% loss. Mortgages are secured by the property, losing investors only a small fraction in foreclosure, so a 2% default * 25% severity = 0.5% loss.

All very good points! Thanks.

If 2% of people default per year you can't go below 2%.

Do we know what were the bottom 30-year fixed rates were after 2008, and how long it took to get there?

No. This is a rate for banks only. You get the rate banks pass on to consumers, which is obviously higher, because they need to make money.

Mortgage interest rates are usually "prime + x". So the prime reducing will reduce "prime + x" by the same amount.

For the same reason, I expect margin interest to drop by the same amount.

It's already a pretty good time to refi for most people as rates dropped to a bit under 3% recently. They went back up a little bit though as mortgage companies had to take on staff to handle all the additional demand.

Shouldn't Broadcom be solely responsible for this? If apple buys a product, why would apple be responsible for details that went into the hardware on BC's end? Not trying to troll - but genuinely trying to understand the logic/law here.

Yup, I think is is called patent infringement indemnification, but I'm guessing lawyers always sue everyone with deep pockets no matter what.

There is also the idea of patent exhaustion, which is that you get your royalties when the thing is implemented (ie the chip) and you don't get any more when that chip is re-sold. Of course Broadcom has some really wild patent "license" deals where they make you license the patent and buy the chips (that is also the subject of a court case)

Are they custom chips Broadcom developed for Apple?

Then there would be a loophole where you make an independent entity that “makes” something that shields infinite liability. It makes sense to go after all beneficiary owners and parties.

I see. So I guess, assuming appeals don't overturn the decision, then Apple needs to sue Broadcom for damages? I don't see Apple left holding the bag in this. Unless they would rather use it as a stick when negotiating future deals with Broadcom.

You mean like they make shell companies for patents so any adverse judgements don't sink the whole boat? Hell yeah, lets have it then.

Could you elaborate on what MLIR has done differently wrt making it multithread safe and what complications it's causing and what the trade offs are..

Sure: for instance in LLVM global values (variables, functions) have use-lists, so do constants. That means you can find easily every uses of a function: they are chained in a doubly linked list. In MLIR, it isn't the case. We use symbol name to refer to other global object, we lose the ability to easily find the uses of these global objects. On the other hand functions are well isolated and you can run Function passes in a multi-threaded fashion safely.

I use TripIt ever since Trips was shutdown. While it doesn't do everything, it does quite a lot (have all reservations etc in one place).

TripIt is a lifesaver for me. I'm sure I'd mess up a lot more than I do if I didn't have an app like TripIt.

My only material beef is that I think it could do a better job of flagging possible oversights in your itinerary. "Umm Dave, I'm afraid you don't seem to have anyplace to stay on Wednesday night."

On complicated trips, I actually print out a calendar grid and make notes by hand. It would be nice if TripIt had a month calendar view that let you look at things that way.

You can export your Tripit itinerary as an .ical and use it with your favorite calendaring app.

Ah thanks. I either didn't know that or I tried it and it didn't really help. I'll take a look at it again on my next long trip.

But basically I'd like TripIt to flag possible problems rather than have me depend on eyeballing it--even though that works OK most of the time.

The printing out of calendar pages is more for trip planning. TripIt doesn't (and isn't really intended to do) anything along those lines.

Based on this recommendation, I signed up, but gracious, the UI is bad.

Ah yah it’s a flashback and not in a good way.

I use and love TripIt but only like this:

0. Subscribe to my personal TripIt calendar feed.

1. Book flight, car, hotel, whatever.

2. Forward booking confirmation to plans@tripit.com.

3. Now all those details are in my calendar.

What’s particularly useful is how it handles time zones. Flights seem to ‘just work’, and in the notes for any appointment it’ll tell you the local arrival & departure times anyway.

You can try kayak trips. I used to use tripit and switched to kayak, the UI is way better.