Liquidity Traders and Random Order Flow in Market Models
Summary
The document explains liquidity traders in a theoretical stock-market setting and contrasts them with informed traders. Liquidity traders act for reasons external to expected asset payoffs, such as client cash needs or portfolio rebalancing. Informed traders instead trade based on private information about future value. Because liquidity traders' timing and motives are not tied to market information, their orders can be modeled as unpredictable to other participants.
In the cited model, liquidity traders submit a random market order, with the random variable representing the quantity they want to buy or sell rather than a price. This exogenous order flow helps distinguish trading driven by liquidity needs from trading driven by information. The explanation draws on an academic definition and examples, but it is conceptual: it does not specify how the order quantity affects prices or provide empirical evidence about actual traders. Real participants may also trade for mixed motives, so the model's categories are simplifications.
Key ideas
- Liquidity traders trade to meet needs unrelated directly to an asset's future payoff.
- Informed traders use private information, unlike liquidity traders whose orders arise for exogenous reasons.
- A random market order represents uncertain buy or sell quantity in the model.
- Client liquidity demands and portfolio rebalancing are examples of motives for liquidity trading.
- The distinction is a modeling simplification, since real trades can have mixed motives.
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Full text
# Liquidity Traders
# Liquidity Traders
I am thoroughly reading my first academic literature and I have found myself overwhelmed by terms that have been generalised in my studies.
The extract is from "The Beauty Contest and Short-Term Trading" by Giovanni Cespa and Xavier Vives, and states
> 'Consider a one-period stock market in which a single risky asset (of liquidation value $v$) and a riskless asset are traded by a continuum of risk-adverse, informed investors in the interval $[0,1]$ and also by liquidity traders.'
Who are liquidity traders? What is their purpose? What's an example of a liquidity trader and how would they contrast with the aforementioned informed trader?
In addition, the paper continues
> 'Liquidity traders submit a random market order $u$, where $u$ is distributed according to $N(0,\tau^{-1})$'
Now I'm curious on the connection between random orders and liquidity traders. In addition, what quantity does $u$ represent?
I apologise for my ignorance.
Regards,
## Answer by Malick (score 4, accepted)
https://quant.stackexchange.com/a/25555
Liquidity traders have no discretion with regard to the timing of their trades. Their trades are triggered by exogenous (to the financial market) reasons and are not related to information.
Then we can not guess/forecast their trades and that's why we can consider the quantity (not the price) they ask/offer as random variables.
> An academic definition : Two motives for trade in financial markets are widely recognized as important: information and liquidity. Informed traders trade on the basis of private information that is not known to all other traders when trade takes place. Liquidity traders, on the other hand, trade for reasons that are not related directly to the future payoffs of financial assets-their needs arise outside the financial market. Included in this category are large traders, such as some financial institutions, whose trades reflect the liquidity needs of their clients or who trade for portfolio-balancing reasons. Admati, A. R., & Pfleiderer, P. (1988). A Theory of Intraday Patterns: Volume and Price Variability. The Review of Financial Studies, 1(1), 3–40. http://doi.org/10.1093/rfs/1.1.3Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.