What is Short: Definition and 523 Discussions

In finance, being short in an asset means investing in such a way that the investor will profit if the value of the asset falls. This is the opposite of a more conventional "long" position, where the investor will profit if the value of the asset rises.
There are a number of ways of achieving a short position. The most fundamental method is "physical" selling short or short-selling, which involves borrowing assets (often securities such as shares or bonds) and selling them. The investor will later purchase the same number of the same type of securities in order to return them to the lender. If the price has fallen in the meantime, the investor will have made a profit equal to the difference. Conversely, if the price has risen then the investor will bear a loss. The short seller must usually pay a fee to borrow the securities (charged at a particular rate over time, similar to an interest payment), and reimburse the lender for any cash returns such as dividends they were due during the period of lease.
Short positions can also be achieved through futures, forwards or options, where the investor can assume an obligation or a right to sell an asset at a future date at a price that is fixed at the time the contract is created. If the price of the asset falls below the agreed price, then the asset can be bought at the lower price before immediately being sold at the higher price specified in the forward or option contract. A short position can also be achieved through certain types of swap, such as contracts for differences. These are agreements between two parties to pay each other the difference if the price of an asset rises or falls, under which the party that will benefit if the price falls will have a short position.
Because a short seller can incur a liability to the lender if the price rises, and because it normally does the short sale through a broker, a short seller is typically required to post margin to its broker as collateral to ensure that any such liabilities can be met, and to post additional margin if losses begin to accrue. For analogous reasons, short positions in derivatives also usually involve the posting of margin with the counterparty. Any failure to post margin promptly would prompt the broker or counterparty to close the position.
Short selling is an especially systematic and common practice in public securities, futures or currency markets that are fungible and reasonably liquid.
A short sale may have a variety of objectives. Speculators may sell short hoping to realize a profit on an instrument that appears overvalued, just as long investors or speculators hope to profit from a rise in the price of an instrument that appears undervalued. Alternatively, traders or fund managers may use offsetting short positions to hedge certain risks that exist in a long position or a portfolio.
Research indicates that banning short selling is ineffective and has negative effects on markets. Nevertheless, short selling is subject to criticism and periodically faces hostility from society and policymakers.

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  1. V

    Why do short circuits have zero voltage?

    I've searched around and all I can find are people quoting the equations. I see it in the math, but it seems contradictory. Here is my line of thought: 1. A source maintains a voltage difference across its terminals. 2. The difference in voltage causes charge to flow from higher to lower...
  2. F

    Friction loss is significant in short pipe

    Homework Statement i was told that the friction loss is significant in short pipe , but not so significant in long pipe . However , the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ? Homework EquationsThe...
  3. S

    Short circuit current and Open circuit voltage -- Illumination

    Homework Statement I'm trying to understand the dependence of short circuit current and open circuit voltage on illumination. Short-circuit current is due to the generation and collection of light-generated carriers -- so does that mean the short circuit current is linearly dependent on...
  4. K

    Weird questions about short circuit current capacity

    Hi friends , today we are just general talking with my boss. and he asked me a question . and that is, if we have equipment that is rated short circuit current is 40kA. for 1 sec. and if we must have to use that same equipment for 3 sec time. that how much short circuit current they can...
  5. A

    Why are UK Masters programs so short?

    I have been looking at some of the theoretical physics programs in the UK and a lot of them seem to be very short 9 months to a year. It just seems insane to learn so much material in such a short amount of time. Is the material covered in the same depth as many U.S. universities? Can someone...
  6. K

    MHB Short questions relating to field extensions

    my book gives a number of short questions, one of which seems trivially simple. Is my solution correct or am I missing the point? 8. If p(x) is irreducible and has degree 2, prove that F[x]/<p(x)> contains both roots of p(x). Soln. Let the two roots be a and b. F(a) is isomorphic to...
  7. I

    Different animal sensory, short and long term memories?

    Is there any research that was done on animal long and short term memories? And short of empirical analysis, if there is none, is there much we could conclude, based purely on what we know about their brains? For example, from knowing which brain parts deal with explicit and which with...
  8. A

    Short circuited illuminated PN junction

    I understand why the potential difference across the pn junction decrease in case of the open circuit, but why does it decrease in the short circuit, And why in the J-V equation we use V = Voc ( where qVoc is the energy between the quasi fermi levels) and what if the quasi fermi levels aren't...
  9. T

    What Happens to Flux in an Induction Motor When Short Circuited?

    Just a curiosity about what happens to the flux, when you short circuit an induction machine. Say there is an initial flux and you're rotating the shaft of an IM and then you short circuit the stator, so no doubt you'll get large currents in the stator, but those large currents, will they cause...
  10. Smattering

    How do you like the short story "They're Made Out of Meat"

    Hello everybody, How do you like the short story "They're Made Out of Meat" by Terry Bisson? http://www.terrybisson.com/page6/page6.html Apparently, this has been circulating online for a very long time already, but I only discovered it recently. Although the story is very short and simple...
  11. R

    Design of a short circuit kit for DUTs (switch, opamp, LEDs)

    Hi folks, I would like to clarify few doubts on my mini-project as mentioned below: I am designing a small kit using a transistor (2N3904) and an OP-AMP (LM741- Voltage follower) with few resistors connected to them. My power supply voltage value is 5V. Please refer to the below picture for...
  12. O

    How a very short λ enable light, not obliterate all shadow? (diffraction)

    Hello all, Guys, I just pointed out that I actually lacking in somewhere in the understanding of the phenomenon of diffraction of light, of which I am aware from no less than 10 years. Recently I revised Huygens wave theory of Light and studied in what ways Newton criticize it. At one of the...
  13. T

    Synchronous Machine Transent parameters from sudden 3phase Short Circuit

    Hi, So we're doing this Lab on Transient reactance of a synch generator and I'm reading Sarma's classic: Electric Machines Steady-state theory and Dynamic performance p. 474-479 But I can't see how to get the actual exponential time constants for the sub-transient and transient reactances? Thanks
  14. 1

    Why the wire burns in short current with flow of current?

    In short circuit it is said that there is no resistance. So the current produce heat and wire is burnt. But as the rise in temperature increase the resistance then in short circuit heat must rise the resistance. How can we say there is no resistance in short circuit?
  15. B

    Short term, Light weight, Low volume Refrigeration Design

    Hello Guys, This is my first time posting here - just wondering if anyone has some insight on a project that I am working on. I want to be able to temperature control an insulated shoe box sized volume at ~5 degrees Celsius for about 20 minutes. The main constraints are that I would need the...
  16. caffeinemachine

    MHB When Does Such a Short Exact Sequence Exist?

    $\newcommand{\Z}{\mathbb Z}$. Question: Let $m$ and $n$ be positive integers. What are all the abelian groups $A$ such that there is a short exact sequence $0\to \mathbb Z/p^m\mathbb Z\to A\to \mathbb Z/p^n\mathbb Z\to 0$. It is clear that any such abelian group $A$ has cardinality $p^{m+n}$...
  17. PeterDonis

    Insights A Short Proof of Birkhoff's Theorem - Comments

    peterdonis submitted a new PF Insights post A Short Proof of Birkhoff's Theorem Continue reading the Original PF Insights Post.
  18. 4

    Short Survey for my EPQ on Artificial Intelligence

    Hi everyone! I'm a sixth form student currently writing an EPQ (5000 word essay) on artificial intelligence. I would appreciate it if you could spare five minutes of your time to take this short survey. I hope you find it interesting. <<link deleted>> Thank you for your time! Rob
  19. E

    Short, intensive physics/math courses

    Hello, I'd like to create a list of short, intensive physics and/or math courses offered around the world. I'm primarily focuses on the U.S. as that is where I live but for the sake of completeness, anywhere would be good. The courses I'm looking should be short, usually 1-3 weeks in length and...
  20. T

    Are the Physics exams in Uni long or short?

    I'm asking because I'm slow when it comes to mathematics in Physics exams , and I was wondering if Universities cater for people who are slow thinkers by making Physics exams longer than high school exams?
  21. M

    Help looking for short presential engineering open courses

    Hi everyone, just wondered if anyone knew about presencial open programs/courses/events/certifications available to engineering students in general, preferably in the areas of mechatronics (controls, electronics) or aerospace engineering. I'm an engineering (undergrad) student from Mexicali...
  22. D

    "Short" PHD at Undergraduate Institution

    The way that my undergraduate career went, I had the opportunity to finish a MS at the same time as my BS within 4 years and now believe I will now have an opportunity to continue my MS to a PhD. I've heard that this typically isn't very good for employment opportunities, but would this be the...
  23. M

    Short method for computing this?

    suppose a side of an equation : 26q+1 , and i want the least positive integer value for q that makes this side of equation divisible by 7, is there any short method to do this ?
  24. PsychonautQQ

    Short Exact Sequence: Explaining C = B/A

    http://en.wikipedia.org/wiki/Exact_sequence Let's look at the following short exact sequence: 0-->A-->B-->C-->0. Since the sequence is exact, the mapping from A-->B will be invective and the mapping B-->C will be subjective. The wikipedia article says that we can think of the mapping A-->B as a...
  25. M

    Confused about short circuit and open circuit

    i know that short circuit is when current is max while resistance is zero and open circuit is when resistance is infinite and current is zero, but in terms of voltage, if i have a part of circuit and i want to know whether it is short or open circuit and i only know : the voltage and if the...
  26. Coffee_

    Lagrangian invariance, short question

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  27. B

    Short Circuit Current in Solar PV Cells

    I'm reading about short circuit current in a solar PV cell and I am a little confused. The short circuit current is defined as the current across the solar cell when there is zero potential difference across the cell. At this point the short circuit current is equal to the light current. What...
  28. C

    Force on a magnet inside a short coil

    The equations are incredibly difficult, so I'm just after a general idea of how the force on a magnet bellow a coil changes with the distance to the coil. Shown bellow: Axial symmetry: o x o x cross section of coil o x o...
  29. Suraj M

    Evolution, short term or long term adaptation?

    I had a small question, which one contributes more to evolution: 1)short term adaptation and heritable 2)long term adaptation and heritable ?
  30. G

    Why doesn't a center tap from a transformer short when grounded?

    Hi everyone, Basic question here. Residential pole mounted transformers and many other transformers that produce a neutral have that neutral "center taped" from a current carrying coil in the transformer and bonded to ground. My question is why doesn't the current in the coil short threw that...
  31. M

    Engineering Using the Short Circuit Test on a Single Phase Transformer?

    Homework Statement A short circuit test is performed on a small single phase transformer. The results are: Primary Voltage 5V, 60Hz Primary Current 2A Secondary Current 10A Primary Power 8W a) Making suitable approximations deduce the primary/secondary turns ratio (single number)? b) Making...
  32. blue_leaf77

    Is Short Communication Appropriate for Mathematical Analysis Revisions?

    So I noticed a mistake in the mathematical analysis in a paper and I want to propose the revised version. What should I do? I think it doesn't worth a journal since the revision probably only takes a page. Is there other ways of doing such revision? I have heard there is this short...
  33. R

    Short Track Inline Speed Skating - 110 mm Wheels vs. 125 mm

    Hi All, New to the forum. I am a lineman by trade so I have an understanding of physics as it applies to not getting yourself killed when setting telephone poles and line tension. I am also a short track inline roller speed skater and they just announced that they will be allowing 125 mm...
  34. T

    Open circuit short circuit (test) TX flux effect

    Hi, It's been a while but from what I remember when you short circuit a transformer, electrically it's like you've series'd up the coils and shorted the magnetisation branch. And when you open circuit a side of the TX it is like the current flows through a side then through the magnetisation...
  35. N

    Current Source in Parallel with Short Circuit

    Homework Statement Which of the following are self-contradictory combinations of circuit elements? - A 2 Amp current source in parallel with a short circuit. Homework Equations KVL- "the sum of voltages around a closed loop amounts to 0. KCL- "the current into a node equals the current out...
  36. Ganesh Ujwal

    A short proof for dim(R[T])=dim(R)+1?

    If ##R## is a commutative ring, it is easy to prove ##\dim(R[T]) \geq \dim(R)+1##. For noetherian ##R##, we have equality. Every proof I'm aware of uses quite a bit of commutative algebra and non-trivial theorems such as Krull's intersection theorem. Recently T. Coquand and H. Lombardi have...
  37. Math Amateur

    MHB Short Five Lemma - Checking Some Simple 'Diagram Chasing'

    I am reading Adhikari and Adhikari's (A&A) book, "Basic Modern Algebra with Applications". I am currently focussed on Section 9.7 Exact Sequences. On page 391 A&A state and prove the Short Five Lemma. I need help with some of the details of the 'diagram chasing' in the proof. The Short Five...
  38. Math Amateur

    LaTeX Latex code for the class SE of short exact sequences in Mod_R

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  39. Math Amateur

    MHB Sub-Category of Short Exact Sequences - Bland pages 85-86

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  40. Math Amateur

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  41. Math Amateur

    MHB Split Short Exact Sequences - Bland - Proposition 3.2.6

    I am reading Paul E. Bland's book, "Rings and Their Modules". I am trying to understand Section 3.2 on exact sequences in Mod_R and need help with the proof of Proposition 3.2.6. Proposition 3.2.6 and its proof read as follows:The part of the proof that perplexes me is the section of the proof...
  42. Spinnor

    "Calabi-Yau Manifold for Dummies", short, at universe-review.ca"

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  43. G

    Is This a Long or Short Rossby Wave at 35o N?

    Homework Statement Consider a Rossby wave propagating in a homogeneous ocean with a water depth of 4,000m at 35o N latitude. If the wave length of this wave is 500km, is this a long or short Rossby wave? Homework Equations shortwaves: |kx-1| <<RD longwaves: |kx-1| >> RD kx is the x-component...
  44. E

    Short Question about Torque on a Ladder Hinge

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  45. R

    Short Cylindrical Vacuum Chamber

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  46. enorbet

    Help Finding a Sci Fi Short (possibly Heinlein)

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  47. Andy Resnick

    A Day Late & a Dollar Short: Contest Results After Nice Weather

    The day after the contest ended, we had nice weather... here's a few that were a day late and a dollar short:
  48. C

    Very very short question on second derivative

    What does it mean when I have to find the second derivative of a circle at a given point? (Implicit diffing) In specifics, the equation is 9x2 +y2 =9 At the point (0,3) You don't really need the rest at all, but it was just my process. This seems to make no sense. first D'v 18x+2yy'=0 Second...
  49. S

    Equivalent resistance with a short circuit

    Homework Statement Find the equivalent resistance of the circuit shown below. Homework Equations R=\Sigma_{i}R_{i} 1/R=\Sigma_{i}1/R_{i} The Attempt at a Solution I'm having a lot of trouble understanding how this circuit can be simplified. All I see is a big short circuit where the...
  50. H

    Short question about length contraction

    The at rest distance between Betty the astronaut and a flag in open space is 1 unit. If Betty approaches the flag at constant speed while laying out metre rulers, will she have laid out 1 unit of at rest rulers when she reaches the flag? Or will the number of rulers laid out exceed 1 due to...
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