Answering this question is more complicated than it may seem at first. There are a variety of reasons why a newsletter may choose to italicize the name of the newsletter, but the most common reason is because it is the name of an organization or company.
Italicizing a newsletter’s name can help to differentiate it from other newsletters that may be published by the same organization or company.
Another reason why a newsletter might italicize its name is if it is a private newsletter and the author wants to maintain anonymity. It can also be helpful for distinguishing a private newsletter from a public one.
Public newsletters are often published with the permission of an organization or company, while private newsletters are typically written by an individual or small group and are not generally known outside of that group.
Ultimately, it is up to each newsletter to decide whether or not to italicize its name. Some newsletters opt to italicize their names while others do not, and there is no right or wrong answer.
It is just something to keep in mind when reading a newsletter and trying to determine which names are being capitalized and which are being italicized.