fastSearch

List<MyObject> largeList = /* your large list */;
List<MyObject> smallList = /* your small list */;

Collections.sort(largeList, Comparator.comparing(MyObject::getTicker));

List<MyObject> matchingObjects = smallList.stream()
                                          .filter(item -> Collections.binarySearch(largeList, item, Comparator.comparing(MyObject::getTicker)) >= 0)
                                          .collect(Collectors.toList());


or 


List<MyObject> largeList = /* your large list */;
List<MyObject> smallList = /* your small list */;

Set<String> tickerSet = largeList.stream()
                                 .map(MyObject::getTicker)
                                 .collect(Collectors.toSet());

List<MyObject> matchingObjects = new ArrayList<>();
List<MyObject> nonMatchingObjects = new ArrayList<>();

for (MyObject item : smallList) {
    if (tickerSet.contains(item.getTicker())) {
        matchingObjects.add(item);
    } else {
        nonMatchingObjects.add(item);
    }
}