Primary ampersand usage varies from language to language. In Germany, the rule is to use the ampersand within formal or corporate titles made up of two separate names.
According to present rules, you may not use the ampersand in running text.
Generally, in English and French writing, the ampersand may be substituted for the words and and et, and both versions may be used in the same text.
How and When to Use the Ampersand
In any language, the ampersand’s lovely calligraphic quality makes it a compelling design element. It can add visual appeal and personality to any page. The ampersand represents the word and in the names of individual companies and law firms, such as in the name Hatch & Marx, LLC.
Except when citing such a name, you should never use an ampersand in place of and in formal writing. Nor should you use a plus sign for this purpose. The word and is always written out.
Originally posted 9/16/2011 and happily updated 10/26/2017. Thanks for reading!