Hou & Moskowitz measure how slowly a stock's price responds to market information (price delay). The most-delayed firms command a large return premium not explained by size, liquidity, or microstructure. Delay captures part of the size effect, and idiosyncratic risk and earnings drift are priced only among the most-delayed (most frictional) firms.
What anomaly it documents
Predictor: price delay — the lag with which a stock's price responds to market-wide information.
Direction: positive — high-delay firms earn a large premium.
Shape: premium concentrated in the most-delayed firms; subsumes part of size.
OSAP predictor: PriceDelayTstat.
How to construct it
Sorting variable: price delay, from regressions of weekly returns on lagged market returns (the R² gain from lags).
Universe: NYSE/AMEX/Nasdaq common stocks.
Portfolio formation: rank into delay deciles.
Long / short: long high delay, short low delay.
Weighting: value-weighted.
Rebalancing: annual/periodic.
Evidence and replication
Period
Notes
Source
IS (1963–2001)
large premium for delayed firms; captures size
this paper
OOS (post-2005)
friction-based premium persists
post-publication
OSAP (PriceDelayTstat)
replicates
Chen & Zimmermann 2022
Why it might work
Limits to arbitrage: delayed firms are neglected and costly to trade, so information impounds slowly and a premium accrues.
Friction proxy: delay summarizes multiple market imperfections in one measure.
Limitations and risks
Microstructure noise: delay estimates are noisy for small firms.
Liquidity entanglement: correlated with size and liquidity.
Tradeability: the premium lives in the hardest-to-trade names.
Key references
Hou, K. & Moskowitz, T. (2005) — Market Frictions, Price Delay, and the Cross-Section of Expected Returns — RFS — DOI: 10.1093/rfs/hhi023
Provenance: generated from the paper's abstract and metadata, not full text; sample periods and replication notes are indicative — verify against the source.
