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.

Using a database of daily institutional trades, we document that a majority of short-term institutional trades lose money. In aggregate, over 23% of round-trip trades are held for less than 3 months, and the returns on these trades average -3.91% (nonannualized). These losses are pervasive across all types of stocks, with the lowest returns occurring in small stocks, value stocks, and low-momentum stocks. Short-term trades lose more in more volatile markets. Across funds, the worst short-term returns accrue to funds that do the most trading, and there is no evidence of persistent skill or disposition effect in short-term institutional trades.

We show that market‐maker balance sheet and income statement variables explain time variation in liquidity, suggesting liquidity‐supplier financing constraints matter. Using 11 years of NYSE specialist inventory positions and trading revenues, we find that aggregate market‐level and specialist firm‐level spreads widen when specialists have large positions or lose money. The effects are nonlinear and most prominent when inventories are big or trading results have been particularly poor. These sensitivities are smaller after specialist firm mergers, consistent with deep pockets easing financing constraints. Finally, compared to low volatility stocks, the liquidity of high volatility stocks is more sensitive to inventories and losses.