Pop Quiz --- selling to yourself

[ShuShu62]

Was chatting with some Nazgul while scratching behind their ear and this topic sort of came up.

Ack... how much would you lose?

[random user]

Odd. I lost 36 (each try), after multiple tries. It also appeared that I lost 33 on my first try but that might be poor record keeping.

Also, I couldn't get the price below I think 55, which is new (and would be good if they implemented that to eliminate the commodity exploit).

[wwjdfakb]

Why am I always the scary nazgul in your posts?

[ShuShu62]

Not scary Weather Goddess.

In fact I can personally attest to disregarding the oldest (leader in Russian) Nazgul's requests multiple times in a heated battle and lived to tell the tale. Turns out the oldest Nazgul is the reason I started experimenting with miracle working and playing as an individual declaring war on the world thus gaining lots of battle experience which casued me to disregard the oldest Nazgul's request. So really it was his fault any way.


---- Note: corrected per random user's pointing out I need more caffeine too ---


soooo... you lose nothing because you are selling at the same price you just purchased at.


Three purchases starting when market is 100-101

100
101 102 103 - 3 buys
xxx xxx xxx 103 102 101 - 3 sells

I could prove this beyond the simple example with Riemann sums, but I don't think my entire readership studied number theory in college. The point is... for each purchase you have a sale at the same price.

Given the trending nature of commodities, armies and great people... you can actually make muoney on the self sale if whatever you bought ticks up before you sell it, but I don't know anybody who exploits that to make money while everyone is sleeping... hehehe

[ShuShu62]

Odd. I lost 36 (each try), after multiple tries. It also appeared that I lost 33 on my first try but that might be poor record keeping.

Also, I couldn't get the price below I think 55, which is new (and would be good if they implemented that to eliminate the commodity exploit).

sorry, poorly written question.

--- edited --- And poorly written answer, thankyou Random for correcting me, and providing reall world evidence that both contradicts the theory and illustrates how hard it is to recreate the true thoeretical case in the real world.
If the price was 100-101 and you bought 100 commodities and then sold....

also, possible explanations for variation could be an up tick from the clock pop while in the middle of your tess. also, once you get below 50, you will get 2 clicks at the same price because of wound off.

I am pretty sure I have seen commodities in the teens within the last couple weeks... allow me to rephrase... I am pretty sure I remember buying many commodities for less than 20 a week or two ago.

[random user]

OK I will clarify myself.

I have a game in which no one logs in anymore. I just recently checked that game (in the time since I've quit I've won 36 civbucks btw... but that's a story for a different day). In that game I had about 110 of one commodity (let's call that commodity A since I don't remember which it was) and about 230 of another (call that commodity B). The price on A was around 700. The price on B was around 400.

For my initial run, I bought 100 of commodity A and then sold off all 100. If the figures I wrote down were correct, I lost 33 gold.

Being not stupid, I decided to get more data points.

I think sold off all 110 of commodity A and recorded my gold total. I think bought 100, then sold 100, and noted that the start bid/ask were the same prior to my buy/sell binge and after. I checked my gold total. It was 36 off.

With 2 different numbers now, I repeated experiment 2. I again got another 36 gold loss.

I decided to see how much price mattered.

I sold off commodity B, but I hit a floor around 50 gold. I couldn't get under it. I don't doubt you saw commodity prices for less than that, but after selling off ~10 at the same price around 50 gold, I was not able to get the visible price lower.

HOWEVER,

After I decided that I wasn't getting the price lower, I noted my gold total, bought 100 of commodity B and sold off 100, and got a really weird total. It was off enough I assumed I made a transcription error. But now I'm not so sure, especially if the visual display and the internal value were different.

After discarding that run, I bought and sold 100 of commodity B three more times -- each time resulting in a 36 gold loss.

OK I logged back in to do more test (yay 3 more civbucks!).

Start: I have 226 marble the bid/ask is 978/958, I have 292,001 gold:
Peak: I have 323 marble (ran out of money) and the bid/ask is 6868/6730 and 2233 gold
Trough: I have 225 marble (misclicked)
End: I have 226 marble the bid/ask is 978/959, I have 291,971 gold

Because I biffed that, let's try that again. Also I'm going to sell some other stuff so I can buy the full 100 marble.

Start: I have 226 marble, the bid/ask is 978/959, I have 492,899 gold
Peak: I have 326 marble, the bid/ask is7326.7179 (I think it just ticked btw), I have 182104 gold
Grr. I need more caffeine.
Trough: I have 225 marble, the bid/ask is 965/945, I have 495,214 gold
End: I have 226 marble, the bid/ask is 984/964 (ok there was a tick so this run is no good), I have 494,249 gold

Switching to Silk:

Start: I have 0 silk, the bid/ask is 542/531, I have 494249 gold
Peak: I have 100 silk, the bid/ask is 4000/3920, I have 323412 gold
End: I have 0 silk, the bid/as is 542/531, I have 494212 gold

Run 2:

Start: I have 0 silk, the bid/ask is 542/531, I have 494212 gold
Peak: I have 100 silk, the bid/ask is 4000/3920, I have 323375 gold
End: I have 0 silk, the bid/ask is 546/535, I have 495346 gold

Hrm another bad set because there was a tick in the middle there.

So let's do runs of 10 since there will be less likelihood of a tick in the middle of the run:

Start: 0 silk, 546/535 bid/ask, I have 495346 gold
Peak: 10 silk, 666/652 bid/ask, I have 489366 gold
End: 0 silk, 546/535 bid/ask, I have 495343 gold

Start: 0 silk, 546/535 bid/ask, I have 495343 gold
Peak: 10 silk, 666/652 bid/ask, I have 489363 gold
End: 0 silk, 546/535 bid/ask, I have 495340 gold

So let's break it down even more:

Here are the 10 buy prices for my silk, in between ticks:

520, 530, 541, 552, 563, 574, 586, 597, 609, 621

and my 10 sells:

621, 609, 597, 585, 574, 563, 551, 541, 530, 520

So that's interesting. 2 of the numbers don't match up. Let's do that again but pay more attention to how much gold I start and end with:

495,253 gold start, 495,251 end. So the gold matches up with the visible display, at least in these two runs.

Preliminary Conclusions
There are probably some rounding issues which occur a little less frequently than 1 in 3, at least in some cases, such as commodities, which cause a little bit of leakage when you buy and sell mass quantities.

Also

100
xxx 101 102 103 -3 buy
100 101 102 - 3 sells

In this example you are neglecting the fact that after buy the 3rd commodity, the bid/ask is now at ~104/103, which means your first sell is at 103, not 102, and your last sale is at 101, not 100.

Just my observations. Feel free to draw different conclusions, and share them! I certainly don't claim to know everything just based on 10 minutes of data gathering on a very small set of trials in a single game.

[ShuShu62]

Thankyou, you are correct. I had originally expected the answer to be zero, option 1. I meant to post it to convince folks who worry about the innefficiency in transfers. But then I hosed up the example and confused mysel. I will correct my earlier post.

It does raise the question of why you are losing any money then when you do the real world observations. I am asuming it is because the roundings are different going up and down, so the market spreads are wider coming down.

consider... 10% difference

If I buy for 100, then the new ask is 100+1 so you see 100-101
If I sell at 101 then the new bid is 101 - 1.01 or market range of 99.99-101

Not sure how they are rounding and calculating the market ranges, but they are slightly different when going up than they are when going down.