Often people refer to "bulk emails" as spam or junk emails, because the term "bulk" leads to unsoliticed, mass emails. From our point of view, if the emailing job is done right, "bulk email" is synonym to a marketing email. Never send your bulk emails all at once, never send them to persons that are likely not to be interested in your offer. When you send bulk emails, make sure your messages do NOT violate the Acceptable Use Policy (AUP) of email or internet service providers.
So, our answer is: if bulk email messages are not sent all at once and they are only sent to people who subscribed to receive your marketing emails, then bulk emails are not spam.
Using the right bulk email software, capable of personalizing the email content and scheduling the sending of emails one by one, you are likely to greatly increase the success rate of your marketing emails.