Abowd (1989)

Abowd, John M. "The Effect of Wage Bargains on the Stock Market Value of the Firm." American Economic Review, September 1989.

Tests whether unexpected increases in labor costs (as defined by an econometric model) result in corresponding declines in stock price. Using NYSE data from 1976 - 1982, finds an inverse relationship between shareholder wealth and union members' wealth.

Link:  https://econpapers.repec.org/article/aeaaecrev/v_3a79_3ay_3a1989_3ai_3a4_3ap_3a774-800.htm