There's much talk about limiting universe of securities and trading only the most liquid stocks. What about algos without universe restrictions? Yes, there are many partially filled and canceled offers, but the results are still very decent. Algo is ranking securities based on it's criteria and trades the ones that get the best score. If the number of securites to choose from is bigger, it gets better candidates for trading and the results are better this way. So, why should i be trading in smaller universe, am i missing something?