Can I make all the letters Bold that shows in the SERP's? And does it gi8ves any advantages SEO wise?
You just type them in bold and see what happens. And I am sure that they don't have any effect in the SERP's.
Hi,
There is nothing effect on SERP's if you bold the letters to promote your
brand!
Making characters bold would not impact in SEO.
Basically they are for user experience and user friendliness so do the math.