Health and life insurance companies in the US and abroad have nearly $4.5 billion invested in tobacco stocks, according to Harvard doctors.

The largest tobacco investor on the list, the 160-year old Prudential company with branches in the US and the UK, has more than $1.5 billion invested in tobacco stocks. The runner-up was Toronto-based Sun Life Financial, which apparently holds over $1 billion in Philip Morris (Altria) and other tobacco stocks.  In total, seven companies that sell life, health, disability, or long-term care insurance, have major holdings in tobacco stock.

Why is it a big deal? “If you own a billion dollars [of tobacco stock], then you don’t want to see it go down,” says Himmelstein, “You are less likely to join anti-tobacco coalitions, endorse anti-tobacco legislation, basically, anything most health companies would want to participate in.”