Trademark symbol in the site title?
You can do this by using HTML TITLE module


  Drupal node titles are restrictive and do not support italicized text
  or superscript text (e.g., Book titles, trademark symbols). The HTML
  Title module allows a limited set of HTML markup (em, sub, sup, b, i,
  strong, cite, code, bdi, wbr) to be used in node titles. It filters
  all other markup from titles to prevent XSS vulnerabilities or
  irrational nesting (e.g., links within links).