NEW YORK -- BlackRock, an investment firm that manages over US$6 trillion in assets, says it is asking gun makers and retailers how they are responding to a high school shooting in Florida, a move that could add pressure on those companies to make changes.

The firm says it is also looking into creating new investment funds for investors that excludes firearm makers and retailers. BlackRock is a major shareholder of gun manufacturers Sturm Ruger, American Outdoor Brands and Vista Outdoor through indirect investments.

Among the questions BlackRock is asking gun makers is if they require retailers to do background checks or flag unusual orders. Retailers are being asked how much profit they make from firearm sales.

The New York-based company says engaging with the companies "has the greatest potential to drive change."