NEW YORK (AP) — Corporate foundations’ philanthropic commitments were called into question this past year as tariff-driven uncertainty , rising costs and tax law changes prompted many companies to reconsider their charitable strategies. Nonprofits received a reassuring answer this week, however, from the century-old, Boston-based Liberty Mutual Insurance. The major insurer’s nonprofit Liberty Mutual Foundation announced Wednesday the establishment of a $600 million endowment, a long-term source