We are a small company that typically sends out < 10,000 emails each month. We have a new client (an extremely large multinational corporation) that wants us to email a portion of their customer base (just under 100,000) on their behalf. These are people who agreed to receive email.
As we haven't had to send that much email before, we're wondering if we should send it ourselves or use a service like Sendgrid or Mailchimp.
Our initial test, however, resulted in a bounce rate of 15%, which is fairly high. I believe that this would result in us being banned by Sendgrid or Mailchimp.
So if that is not an option, we will send them ourselves. But if we suddenly start sending out 100,000 emails in the course of a day or two, will we be pegged as spammers?