But by deselecting an exchange you can ignore results from companies on that particular exchange. If your search found any results, they're listed in a table. You should see columns for the company name, the company's stock ticker symbol, a recent stock quote, the patent number, issue date, and patent title. Clicking on the stock ticker should bring you to yahoo, which can provide you with a more up to date stock quote. Clicking on the patent number will bring you to the actual patent at the US Patent Office.
Stock prices are only updated weekly.
I never intended to provide stock quotes on this site, they merely serve as a relative indicator. This is probably the greatest source of error. The difficulty is matching the name from the assignee of the patent to a public company. To make things more difficult, sometimes the name is abbreviated or otherwise different than what I'm looking for. Another deficiency is the search engine does not know about subsidiary companies.