You should be aware that multiple e-mails from a single IP address, all with the same subject line, is almost the definition of spam, so even a seemingly innocent activity like e-mailing Adagio AR statements can be a challenge in today's spam-infested world.

Mass e-mails with attachments are always more suspect to spam filters than mass e-mails without attachments.

There are sites on the Internet where you can find out if your ISP or mail host's IP address is blacklisted or has a low score. This can cause some of your e-mails to be blocked by some span filters.

As a last resort, you might want to Google SPF or DKIM, both of which can give a mass e-mail sender increased credibility.