Unwinding Stochastic Order Flow: When to Warehouse Trades

Fuente: arXiv
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Main Authors: Nutz, Marcel, Webster, Kevin, Zhao, Long
Format: Preprint
Published: 2023
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author Nutz, Marcel
Webster, Kevin
Zhao, Long
author_facet Nutz, Marcel
Webster, Kevin
Zhao, Long
contents We study how to unwind stochastic order flow with minimal transaction costs. Stochastic order flow arises, e.g., in the central risk book (CRB), a centralized trading desk that aggregates order flows within a financial institution. The desk can warehouse in-flow orders, ideally netting them against subsequent opposite orders (internalization), or route them to the market (externalization) and incur costs related to price impact and bid-ask spread. We model and solve this problem for a general class of in-flow processes, enabling us to study in detail how in-flow characteristics affect optimal strategy and core trading metrics. Our model allows for an analytic solution in semi-closed form and is readily implementable numerically. Compared with a standard execution problem where the order size is known upfront, the unwind strategy exhibits an additive adjustment for projected future in-flows. Its sign depends on the autocorrelation of orders; only truth-telling (martingale) flow is unwound myopically. In addition to analytic results, we present extensive simulations for different use cases and regimes, and introduce new metrics of practical interest.
format Preprint
id arxiv_https___arxiv_org_abs_2310_14144
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Unwinding Stochastic Order Flow: When to Warehouse Trades
Nutz, Marcel
Webster, Kevin
Zhao, Long
Trading and Market Microstructure
Mathematical Finance
91G10
We study how to unwind stochastic order flow with minimal transaction costs. Stochastic order flow arises, e.g., in the central risk book (CRB), a centralized trading desk that aggregates order flows within a financial institution. The desk can warehouse in-flow orders, ideally netting them against subsequent opposite orders (internalization), or route them to the market (externalization) and incur costs related to price impact and bid-ask spread. We model and solve this problem for a general class of in-flow processes, enabling us to study in detail how in-flow characteristics affect optimal strategy and core trading metrics. Our model allows for an analytic solution in semi-closed form and is readily implementable numerically. Compared with a standard execution problem where the order size is known upfront, the unwind strategy exhibits an additive adjustment for projected future in-flows. Its sign depends on the autocorrelation of orders; only truth-telling (martingale) flow is unwound myopically. In addition to analytic results, we present extensive simulations for different use cases and regimes, and introduce new metrics of practical interest.
title Unwinding Stochastic Order Flow: When to Warehouse Trades
topic Trading and Market Microstructure
Mathematical Finance
91G10
url https://arxiv.org/abs/2310.14144