This paper deals with modeling brokered segments of a ‘fast’ security market, meaning a
market characterized by three interrelated features:
- A large number of participants who place orders within a narrow time span;
- Very short-lived motives for trade (frequent changes of desired positions); and
- Uncertain terms of individual trade for any given participant due to a high
concentration in time of other participants’ actions.
The three named elements are typical for electronically brokered trading in many upperend
stocks, bonds and major currencies. (An electronic FX broker for a frequently traded
currency pair is among the best examples of a fast market.) Electronic brokerage systems with
fully or partially1 observable books are now implemented by most exchanges around the
world. A market for any top-tier security traded there would meet our criteria.2 In addition,
there exists a special category of ‘high-frequency traders’ who exploit short-lived arbitrage
opportunities with the help of computerized trading, making the market for the involved
instrument even faster. It is known that all but the biggest high-frequency traders operate through brokers, i.e., contribute to increased trade frequency in order-driven markets.
Therefore, formalizing the physiology of a continuous double auction under fast market
conditions without resorting to the zero-intelligence simplification should be of interest for
practitioners. No less pertinent is this task for understanding asset price deviations from
fundamentals, the phenomenon actively researched by financial economics, e.g., in the context
of exchange rate (or risk-free bond yield) disconnect conundrum. Although, at present, the
majority of transactions in this asset class happen in fast order-driven markets, the latter
have been largely left unexplored by theoretical literature, at least that part of it which draws
on individual rationality. Consequently, existing theories of continuous double auctions say
very little about the properties of price discovery resulting from high frequency of orders and
trades.
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