Nonprofits annually lose an average of nearly $15,000 because of fundraising solicitations intercepted by spam filters, according to a new study.

Donations made in response to emails accounted for about a third of online fundraising revenue in 2013, but one in eight emails never reaches an inbox — a percentage almost as high as the share of emails that are opened, the report says. Nonprofits could boost email fundraising revenue by around 14 percent by reducing their spam rate.

An organization’s emails may be sent directly to the junk mailbox — or not delivered at all — when an Internet Service Provider notices that many of its users are marking emails from a certain IP address as spam. Other triggers are emails from a sender that frequently are deleted without being read or are never opened.

href="#" data-color-override="false" data-hover-color-override="false" data-hover-text-color-override="#fff">Button Text