Earnings announcements and attention constraints: The role of market design
We identify a new channel – market makers’ attention constraints – through which
earnings announcements for one stock affect the liquidity of other stocks. When some
stocks handled by a designated market maker have earnings announcements, liquidity
is lower for non-announcement stocks handled by the same market maker, with the
largest effects coming from earnings surprises and stocks with high earnings response
coefficients. Half of the liquidity decline reflects attention constraints binding on the
individual market maker, and the other half is explained by the market maker’s
inventory. We further find that a market design change that increases automation
alleviates the liquidity effect of attention constraints, despite an increase in the number
of stocks allocated to each market maker