BMO Bank of Montreal. Im speechless over how incompetent they are. (Canada)

Nestle. Because they're evil.

Others?

Edit:

See also the positive inverse of this post: What is a business/org that is great and ethical in so many aspects that everyone should consider using?

Inspired by https://tildes.net/~life/1q0v/what_is_a_business_org_thats_so_terrible_no_one_should_use_if_possible

If you're finding it hard to come up with something, remember that medium, small, and local businesses do exist ;)

Also, good deeds are not enough; their product must be awesome too!

If at all possible, let's keep this positive!