Investors should sell their First Solar Inc. shares and pocket the big gain the solar panel maker's stock has made in recent months, according to a report in Barron's.

First Solar stock has risen 54 percent since the end of September, when Barron's published a story predicting U.S. tariffs on solar modules and cells, the publication said in a report in its Jan. 29 issue.

U.S. President Donald Trump on Tuesday signed into law a 30 percent tariff on fully assembled imported solar panels as well as the cells of which they are made.

U.S.-based First Solar is exempt from the tariff but has benefited from a surge in demand in recent months from utility customers who have wanted to fulfill their solar needs ahead of the tariff, Barron's said.

First Solar shares closed at $70.56 on Friday.