In view of the growth and popularity of defined contribution pensions, along with the government’s growing attention to retirement plan costs and investment choices provided, it is important to evaluate how people select their plan investments. This paper tracks how employees in a large firm altered their fund allocations when the employer streamlined its pension fund menu, tiering options in an easier-to-understand format. Using administrative data, we examine what investment choices the plan participants elected prior to and after the streamlining, and how they altered their equity share, risk exposure, fees paid, and turnover patterns as a result of the change. We also discuss what difference the changes might make for participants’ eventual retirement wellbeing. Specifically, we show that streamlined participants’ new allocations exhibited significantly lower turnover rates and expense ratios; based on reasonable assumptions, this could lead to additional aggregate savings for these participants over a 20-year period of 20.2M,orinexcessof9,400 per participant. Moreover, after the reform, streamlined participants’ portfolios held significantly less equity and exhibited significantly lower risks by way of reduced exposures to most systematic risk factors, compared to their non-streamlined counterpart