BrightScope, an independent financial information company, and Target Date Analytics, which provides analysis, theory and benchmarking of target-date funds, recently released their newest study in their "Popping the Hood" series, providing a detailed analysis of target-date funds and fund families.

The study notes that TDF assets continue to grow as a percentage of total defined-contribution assets, with BrightScope projecting that target-date assets will reach $2 trillion in 401(k) plans by 2020.

The study says that target date funds continue to make "huge in-roads into the marketplace," with the primary distribution channel being DC plans because 401(k) participants want a "buy and forget" strategy where they don't have to worry about rebalancing their portfolio regularly, and because the Department of Labor allows TDFs to be a qualified default investment alternative.