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(Mark Hulbert, an author and longtime investment columnist, is the founder of the Hulbert Financial Digest; his Hulbert Ratings audits investment newsletter returns.)

CHAPEL HILL, N.C. (Callaway Climate Insights) — If you’re interested in influencing corporations’ climate policies, you should actively engage with their management. Merely shunning “bad” firms and investing in “good” ones might make you feel good about yourself, but it is a relatively ineffectual way of changing firms’ behavior.