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

“It’s the combined taxidermist and veterinarian approach: either way you get your dog back,” says David Himmelstein, an internist at the Harvard Medical School and co-author of a letter published in this week’s issue of the New England Journal of Medicine.

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.