We consider a model of wage determination with private information in an oligopoly. We investigate the effects of unions having relative concerns on the negotiated wage and the strike activity. We show that an increase of unions' relative concerns has an ambiguous effect on the strike activity.
Mauleon, A., Vannetelbosch, V., & Vergari, C. (2014). Unions’ relative concerns and strikes in wage bargaining. Bulletin of Economic Research, 66(4), 374-383. https://doi.org/10.1111/j.1467-8586.2012.00455.x (Original work published 2014)