I am sure they make money on the float.
For those that don't know this is how Warren Buffet started his empire. He had a reinsurance company with a net worth of ~$1,000,000. They took in premiums of about 100 million a year and put them in interest bearing accounts paying 4-5%. Even if they paid out 100% of the premiums they took in on claims they still showed a gross profit of 40-50% of the company's net worth.