Change the calculation in your web viewer to:
"https://www.google.com/finance?q=" & Stock name
where "Stock name" is the name of your field. This should redirect the web viewer to the appropriate detail page.
As an aside, in order to determine the appropriate URL for a web viewer, you can go to the site in question and do what you want. Then, view the URL in the browser bar. Reconstruct this URL using the FileMaker calculation engine and, in most cases, it will reproduce the result you need.
Thank you Mike. I appreciate the answer and as well the aside.