3 ETF themes for an improving economy and cleaner energy in 2021

A contractor for First Solar works on construction of the Tenaska Imperial Solar Energy Center South project in Imperial County, California.
Sam Hodgson | Bloomberg | Getty Images

Investors should increase their exposure to metal miners, clean energy and Chinese stocks to maximize their returns in 2021, according to Astoria Portfolio Advisors' John Davi.

Stocks in these groups have been on a tear this year amid increasing expectations of an economic recovery as well as potential changes to the regulatory environment in energy. For example, metal miner Freeport-McMoRan is up nearly 88% year to date, while First Solar has rallied 81.7%.

Davi thinks investing around these themes can yield even more returns in the new year, and he advises investors to use exchange-traded funds to play them.