It could hash the contents of a dir. Along the lines of git

Except hashing requires... reading.

There is not much to be done here. Directories entries are just names, no guarantees that the files were not modified or replaced.

The best you could do is something similar to the strategies of rsync, rely on metadata (modified date, etc) and cross fingers nobody did `cp -a`.

I would be fine with the latter, the program could display a warning like "Results may be inaccurate, full scan required" or something.

I guess I'm just annoyed that for Windows/NTFS really fast programs are available but not for Linux filesystems.

And to hash something needs reading all of its data. I think deducing the file size would actually be faster in some file systems and never slower with any.

Faster in all file systems I'd guess, stat is fast, opening the file and reading its contents and updating a checksum is slow, and gets slower the larger the file is.

Can't quite get my head around their strategy. Can someone clarify? My understanding is that the bought WTI in the TAS market and at the same time sold WTI to drive the price down (It's not clear when did they buy this WTI or if they maded a profit selling them or were just driving the price down). When the price hit –$37.63 at the end of the day the WTI they bought at the TAS market had to pay them, right? That were they made their profit?

their view was the price was going to drop during the day. so they entered into contracts to buy oil at the end of the day, at whatever the prevailing price was. Now they are long oil. During the day they sell oil futures, flattening their position. Net at end of day, they're contracted to buy at some price, but contracted to sell at a bunch of higher prices. Hence in the money.

My basic maths implies they sold - and bought - 10k lots, which is 10m barrels. So a huge position.

The interesting part of this trade is that their TAS trade was “in the money” at the same time their long positions were.

That’s not supposed to happen. Your hedge should cost you profit but because of oil going negative both sides of their trade were profitable.

When did they buy these oil futures which they were selling throughout the day?

It may have been more or less at the same time. Commit to buy X shares at the close; sell X shares now. Or vice versa.

A futures "buy" is not an actual buy. Its an agreement to buy at some agreed price at some point in the future. So they entered into agreements to sell during the day, then effectively covered that commitment by entering into agreements to buy at the end of the day.

The TAS contracts required them to buy at settlement price. They obviously did not want inventory so they sold an equal number of contracts. (Sell high, buy low). That much is a routine short scenario.

The unusual part of this scenario is that contracts were expiring (it required someone to take actual inventory) so prices at settlement went negative. So when they "bought" to cover their shorts at settlement they were paid to do so.

Another question. Once the future expires they have to take in that oil physically. Did they do that and sell in the regular market?

No. They sold an equal number of future contracts so they were flat and did not need to take inventory. That part is a routine shorting scenario. The odd part of this is that market conditions caused demand to drop so far that sellers paid buyers to take the contracts (and inventory). So these guys were paid to honor their TAS contract but had already sold the inventory to others via the futures contracts.

To put in a simpler terms, they didn’t have to take delivery, because they sold the oil earlier in the day to someone else. Since they didn’t have any oil at the time, they sold it “short”. Then, at the end of the day when they “bought” the oil at the negative prices, it was used to cover the contracts for the oil they sold earlier in the day.

Please tell me if I’m correct:

1. Sell futures contract At $15 (bearish position)

2. Buy futures at TSA when it’s negative - an equal amount to the ones u sold- to cover the futures you initially sold

Yup. When the price at the end of the day is negative, you get money both when you originally sell, and also when you later buy.

Please tell me if I’m correct: 1. Sell futures contract At $15 (bearish position) 2. Buy futures at TSA when it’s negative - an equal amount to the ones u sold- to cover the futures you initially sold

So basically they sold the contract earlier in the day for a higher price and then and covered their position at a much lower price.

Assuming I’m correct: My question is, doesn’t this require margin? If so, how much? What was their initial cash position?

I think the point is they buy them as TAS, then sell what they've bought before they've settled.