public Integer getWorstBorrower() {
        Map<Integer, Integer> total = new HashMap<Integer, Integer>(), current;

        for (Integer id : this.stock.keySet()) {
            current = this.stock.get(id).getWorstBorrower();
            for (Integer w : current.keySet()) {
                total.put(w, total.containsKey(w) ? total.get(w) + 1 : 1);
            }
        }

        Integer index = -1, max = -1;
        for (Integer id : total.keySet()) {
            if (total.get(id) > max) {
                index = id;
                max = total.get(id);
            }
        }

        return index;
    }