(within 15 years of retirement), experience a 7.2 percent wage increase with treatment even as their pension program participation remains unchanged. We observe no similar increase in the wage earned by the younger sample, even as they increase participation in the urban employee pension program. Thus, while older workers can expect to gain less from pension enrollment, the information intervention appears to have facilitated a bargaining outcome in which they have split the surplus from not participating with their employers. In the RUMiC cities, where the average employee contribution is 8% and the employer contributes between 14% and 21%, the magnitude of the “bargained” outcome makes intuitive sense: employers grant some higher return to employees, but generally less than half of the mandated employer contribution.<sup>18</sup> As both employers and employees lose contributions made to the urban employee pension fund on behalf of older employees, it is incentive compatible for both older workers and their employers to engage in this type of bargaining.

**Heterogeneity of Treatment with the Relative Premium.** Apart from possessing a contract, differences in relative premium levels across cities may also introduce heterogeneity in the treatment effect. To understand the potential for this heterogeneity, Figure 2 plots the unconditional city-level treatment effect versus the relative premiums for health insurance and pension programs, respectively.<sup>19</sup> A significant negative relationship is observed for health insurance: in cities with a higher relative premium the unconditional treatment effect was negative between 2015 and 2016, while in cities with a low premium, we observed a positive increase in participation. With respect to pensions, one observes no association between participation and premiums, but this is driven by one city, Luoyang. Excluding Luoyang one also observes a negative relationship, but this is much weaker than for health insurance. Thus, it is plausible that in cities where premiums were high, migrants decided to withdraw from social insurance once informed of prices and benefits, whereas participation rates increased subsequent to receiving information in those cities where premiums were relatively low.

To allow for the treatment effect to vary with local health insurance and pension premiums, equation (3) is next estimated and results are presented in Panel A of Table 4. Recall that in this specification, the included city fixed effects control for differences in labor market conditions across cities, the average earnings of migrants and in the unobserved city-level

> 18Based on conversations with both migrants and their employers, researchers have believed that this bargaining outcome exists (Giles et al., 2013; Meng, 2017), but the wage response of older workers who cannot fully benefit from pension participation offers the first corroborating empirical evidence that informed workers may bargain with employers for higher wages.

> 19 Specifically, we first obtain coefficients from the health insurance and pension participation models estimated with city-specific information treatment indicators (city dummies interacted with the information treatment) in models that control for the city fixed effects and then plot the coefficients on the city-treatment interactions against the city-level relative health insurance and pension premiums, respectively.

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