Email may be a go-to for marketers, but many of those messages aren’t reaching customers’ inboxes. According to new data, only about one-third (32%) of legitimate emails are reaching consumer inboxes.

With the holiday shopping season behind us, new data may put a damper on some merchants’ post-holiday expectations, especially those relying on email to connect. According to new data, only about one-third of marketing messages are reaching customer inboxes.

Researchers with FireEye found that through the first half of 2018 only about one-third of emails reached consumer inboxes, a disturbing note considering email continues to be a top way for merchants and marketers to reach their customers. Other reports have shown that email is a preferred marketing channel for consumers, too.

“Not only is email the most pervasive form of communication, but it is also the most popular vector for cyber attacks. This makes email the biggest vulnerability for every organization,” said Ken Bagnall, vice president of email security at FireEye. “From malware to malware-less attacks including impersonation attacks like CEO fraud, a single malicious email can cause significant brand damage and financial losses. By choosing an email security solution with features based on real-time knowledge gained from the front lines, and by teaching users always to ensure they are communicating with who they think they are, organizations can better defend against attacks.”

FireEye’s Email Threat Report further found that Monday’s and Wednesdays are the most common days for malware-based attacks, with Thursday being the least-likely attack day. Attacks without malware were most likely to occur over a weekend and impersonation attacks most likely to occur on Fridays.