Django bulk insert with Foreign Key

FK.py

from stocks import wsgi
from django.core.exceptions import ObjectDoesNotExist
from api.models import Stock, Company

import csv

csvpath = r'prices.csv'
batch_size = 500

t1 = time.time()

with open(csvpath) as csvfile:
    reader = csv.DictReader(csvfile)

    stocks = []

    for i, row in enumerate(reader):

        try:
            company = Company.objects.get(symbol=row['symbol'])
        except ObjectDoesNotExist as e:
            company = None

        s = Stock(date=row['date'],company=company,....)
        stocks.append(s)
        if i % batch_size == 0:
            Stock.objects.bulk_create(stocks)
            stocks = []
    Stock.objects.bulk_create(stocks)

t2 = time.time()
print(t2-t1)