Marjory Stoneman Douglas High School student David Hogg speaks onstage at March For Our Lives on March 24, 2018 in Washington, DC.

One of Parkland, Fla.'s most prominent student activists on stopping gun violence has called for a boycott of Vanguard and BlackRock, two of the world's biggest investors in gunmakers.

In a post on Twitter on Tuesday, David Hogg remarked on the firms' ownership of gun maker stocks, adding "if you use them, feel free to let them know." Then he added two tags: BoycottVanguard BoycottBlackrock.

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Hogg led a successful advertiser boycott of Fox television's Laura Ingraham's show last month after Ingraham publicly mocked his college acceptances. Hogg survived the shooting at a Florida high school in February that left 17 people dead. Since then, he and fellow classmates have led a nationwide protest movement over gun violence.

BlackRock and Vanguard, giant managers of exchange traded funds and other passive-style investments, are the biggest owners of publicly traded firearms makers like Sturm Ruger and American Outdoor Brands. That's because these funds track stock indexes that include the stocks of the gun makers.

BlackRock recently said it had created new funds that would exclude those stocks for investors that wanted to avoid owning them. The fund manager has also said it is in active conversations with gun makers about their businesses.