Cash, Net Exposure, and Gross Exposure in Market-Neutral Portfolios
Summary
The document explains why a long-short portfolio can hold substantial cash even when its positions are described as weights of net asset value. Short-sale proceeds increase the account’s cash balance, while the short positions remain liabilities with their own price risk. Cash is therefore the residual needed for the long positions, short-sale proceeds, and portfolio value to reconcile. In the example, long and short weights differ, leaving a positive net exposure and a larger gross exposure.
The answers distinguish net exposure, the difference between long and short weights, from gross exposure, their absolute sum. They also caution that “market neutral” can refer to different targets, including dollar or beta neutrality, or a spread based on another relationship. One response speculates that a scaling calculation may increase long exposure while preserving balance, but the original context is insufficient to confirm its purpose. The discussion clarifies accounting and exposure concepts, but it does not assess the portfolio’s actual market beta, financing costs, borrow risk, or whether its construction achieves neutrality.
Key ideas
- Short-sale proceeds contribute to portfolio cash while the short positions remain risky obligations.
- Cash can be the residual that makes portfolio weights reconcile to net asset value.
- Net exposure is the difference between long and short weights.
- Gross exposure is the sum of the absolute long and short weights.
- Market neutrality may target dollars, beta, or another relationship, so the intended definition matters.
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Full text
# market neutral weights and cash values # market neutral weights and cash values I am looking at a market neutral portfolio and have a question which I think is probably pretty simple. So I can see the individual stock weights. ``` The sum of the longs is 0.83 The sum of the shorts is -0.78 ``` So the net weight is 0.05. The weight of the cash part is 0.95 giving a total weight of 1. Is this normal for a market neutral or long short portfolio to have that much cash? I'm obviously missing something here. I also have an addition question. I then see that with these weights they do the following manipulations to get 'fully invested portfolio', (the weights above summed to 1 so not quite following why the below is required). ``` someMultiplier = 0.95 / sum of the longs (i.e 0.83) someMultiplier = 1.144578 wgts = all wgts (excluding cash) * someMultiplier cash = 1 - wgts ``` What are they doing here? The cash value is approx 0.94 ## Answer by nbbo2 (score 2, accepted) https://quant.stackexchange.com/a/19397 Yes, it is normal for a L/S fund to have a lot of cash. When you short securities your account is credited with the proceeds from the sales. So if you short 1 million of stock you end up with 1 million cash and -1 million short stock position. Another way to look at it is: as you mentioned, the weights as a fraction of NAV have to add up to 1.0 by definition and cash can be seen as mechanically determined by that identity [i.e. cash=1.0-0.83+0.78]. What the other calculation is about I have NO IDEA. Maybe the "normal" long exposure they want is 0.95 rather than 0.83 and they are trying to adjust for that. Do they mention what they mean by "fully invested"? ## Answer by mt_christo (score 1) https://quant.stackexchange.com/a/19405 Market-neutral portfolios seek to eliminate market risk, so sum of the weights could be even a zero. That would mean that you bought a lot of some equity, and then borrowed some other equity and sold it. You have cash now, but you also have risks, because you will have to return the borrowed equity in the end, and who knows how much you will have to pay to buy it back from the market. So you have twofold price risks. There's a difference between Net Exposure (in your case, it is 0.05) and Gross Exposure (in your case, it is 0.83 + 0.78 = 1.61). As for the code provided: I think it seeks to keep the balance of longs and shorts, while increasing the long weight to 0.95. At least, that's what it looks like if you consider "wgts" a vector. Hope that helps! ## Answer by pincopallino (score 0) https://quant.stackexchange.com/a/19445 In addition to the previous comments, I would like to add that are plenty of definitions for market neutrality. You can for instance be market neutral in dollars, or market neutral in beta or running a spread based on some other mechanics (f.ex. cointegration) Some more info would help better answer your question.
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