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A comment on Oil plunges below zero for first time with May contract ending. Parent comment

Re:Oil plunges below zero for first time with May contract e... by patall on Monday April 20, 2020 @05:38PM (#22928895)
Interesting math question: When we now start at a negative price tomorrow, what does a percentage change mean? Today, we have got losses >100%, unusual but obviously possible. But if price changes tomorrow from say $-10 to $10, is that again -200%? Does a change from $-10 to -$20 mean +100%?

(I obviously know percentage changes are not made for this)

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Re:Oil plunges below zero for first time with May contract e... by symplee on Monday April 20, 2020 @07:26PM (#22930033)
Follow up question: If it had ended at zero dollars, then the next day jumps to $5, what's the percentage change?
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Re:Oil plunges below zero for first time with May contract e... by marcosdumay on Monday April 20, 2020 @11:13PM (#22931469)
Follow up answer, it's never zero dollars.
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Re:Oil plunges below zero for first time with May contract e... by marcosdumay on Monday April 20, 2020 @11:12PM (#22931465)
Hum... We can know this today with the power of Math!

But seriously, changing to -$10 to -$20 is a +100% change. It's multiplication, this is how it works. From -$10 to $10 would be a -200% change.

Obviously, only the mainstream news reports finance numbers as a percentage of change. Anybody else is only concerned about ROI.

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Re:Oil plunges below zero for first time with May contract e... by patall on Tuesday April 21, 2020 @04:29AM (#22933090)
Well, NYSE stops at certain drop intervals, so percentage does also occur professionally:

https://en.wikipedia.org/wiki/Trading_curb

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Re:Oil plunges below zero for first time with May contract e... by jVinc on Tuesday April 21, 2020 @06:27PM (#22940011)
If I take 10$ to take some asset, and then later sell it for 20$ my return is 30$ and my investment was -10$, so my ROI comes out as -300% which betrays what's going on. So even with ROI, negative numbers throws a wrench in the machinerys typical assumptions.
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Re:Oil plunges below zero for first time with May contract e... by gberger on Monday April 20, 2020 @07:24PM (#22930020)
I guess we'll find out tomorrow
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