The limitation on the number of tickers is the general URL length limitation of around 2000 characters (Max URL length for Internet Explorer is 2,083 characters). As a rule of thumb, we suggest 200 symbols as a maximum per call, but there’s no limitation to the number of calls you can make in production, so you can call the universe concurrently if needed.
This is applicable to all the API Endpoints that take multiple identifiers as input (Example: GetGlobalDelayedQuotes)