Percent Calc Problem

[earth_imperator]

yep.
The water under which this trade exists (the negative value) is half as deep at the second measurement point as it was at the first measurement point.
fitty. lol
Secondly, of what value is knowing this redonkulous measure in the first place.

It's even of paramount importance for some trading scenarios involving negative balances, for example when using stock or option shorting and then having a (temporary) drawdown of more than -100%, but then partially rebounding... Ie. a universal growth function (ie. percent and percent change for all values, incl. negative ones).
Also important for VaR and margin calculations at brokerages and exchanges...

 

[SunTrader]

From -200 to -100 is a gain, a 100% gain, ie. a doubling.

I was referring to proper usage - that you claim I didn't use.

Anyway from -200 to -100 is a reduction in paper loss (upto that point), not a gain of any kind.

 

[easymon1]

The debt was reduced by 100%, not 50%.

fitty.
So yes your debt was reduced from 200 to 100. Half as much debt. fitty.
Is this mute9003? lol.
Make better trades and you won't have these meaningless measurements?
Party on wayne.
fitty.

 

[earth_imperator]

fitty.
So yes your debt was reduced from 200 to 100. Half as much debt. fitty.
Is this mute9003? lol.
Make better trades and you won't have these meaningless measurements?
Party on wayne.
fitty.

I've no clue what you mean by "fitty" (I first assumed you mean "fifty" percent ).

Make better trades and you won't have these meaningless measurements?

I'm writing software for a startup brokerage where such functions are needed to calculate PnL%Chg for each trader as well for calculating portfolio margin risks and margin requirements...

 

[Robert Morse]

https://www.sterlingtradingtech.com/products/risk-and-margin-system/ I'm not sure what you mean by write the software. Maybe it would be best to partner with a company that built that already. We use this for firm risk and offer to PM Accounts.

I'm writing software for a startup brokerage where such functions are needed to calculate PnL%Chg for each trader as well for calculating portfolio margin risks and margin requirements...

 

[earth_imperator]

https://www.sterlingtradingtech.com/products/risk-and-margin-system/ I'm not sure what you mean by write the software. Maybe it would be best to partner with a company that built that already. We use this for firm risk and offer to PM Accounts.

Thanks Robert, will contact them. I'm a programmer & SW dev & SW eng & SW arch & part-time trader & and and and...

 

[Robert Morse]

I can put you InTouch with the head of risk at STT. He is also the head of risk at Lightspeed. Just email me your contact info and a brief description I can forward to him.

Thanks Robert, will contact them.

 

[longandshort]

If you’re struggling with basic maths I’m not sure how well your software will pan out.

A loss of -200 to -100 means you reduced your loss by half, or 50%.

Simple formula for % gain is New/Old-1. You never ever get 100%.

You cannot say “I doubled my loss” or “my loss increased by double” or “my loss reduced by double” when describing “-200 is now -100”.

 

[easymon1]

I've no clue what you mean by "fitty" (I first assumed you mean "fifty" percent ).

I'm writing software for a startup brokerage where such functions are needed to calculate PnL%Chg for each trader as well for calculating portfolio margin risks and margin requirements...

... keep us posted?

 

[earth_imperator]

@longandshort, FYI: let me tell you that negative territory is a mystery itself. Things are much different, maybe mirrored. I'm for more than a week now experiencing & experimenting with all the possibilities and seeking a general solution, including when the # intervals (aka # periods, n) is different than 1, ie. compounded interest and its inverse functions (solved for p, n, startcap). It's a handful functions all dealing with percentages: endcap startcap, periodpct, periods, pct, pct_chg, ... where n can also be fractional (but >0) and startcap and endcap can also be negative, as well p can not only be negative, but can even be less than -100%...
It's IMO a real math challenge