How to look up which ticker symbol Numbers uses for a preferred stock?

I use the live stock quote feature in Numbers to track a portfolio of stock holdings. But sometimes a stock trades under different ticker symbols on different services. For instance, preferred shares and shares on foreign exchanges are listed under different tickers depending on whether you're looking at Yahoo Finance or TDAmeritrade....or Numbers. Most of the time in these cases I keep guessing until I get the ticker symbol correct and Numbers recognizes it. Is there a way to do a symbol lookup in Numbers? Or, does anyone know what service Apple uses to provide the stock quotes, i.e. Yahoo or Google or Bloomberg etc? Specifically, right now I cannot figure out how to make Numbers recognize EQC preferred shares, which trade under EQC-D on TDAmeritrade and EQC-PD on Yahoo. Neither of those are recognized by Numbers.