Co-insurance simply means sharing the burden of paying for expenses along with an insurer such as Cigna TTK Health Insurance. Since the burden of payment is shared, the premium is correspondingly lower.Example: Raj has 20% co-insurance for his health insurance policy. He had to undergo a surgery recently. The total expense of the surgery came to Rs. 20,000. Raj while enrolling for his medical insurance policy opted for 20% co-insurance. This means that Raj would have to bear 20% of Rs. 20,000, i.e., Rs. 4,000 on his own, while Cigna TTK Health Insurance would bear the balance 80% of the expense or Rs. 16,000.Also, consider another situation. Raj has opted for a 20% co-insurance and a Rs. 2,000 deductible in order to reduce his premium amount. In this case, if the total medical expense amounts to Rs. 20,000, Raj would first pay Rs. 2,000 and then cover 20% of the balance Rs. 18,000. This implies he would incur, Rs. 2000 plus 20% of Rs. 18,000 or Rs. 5,600 in total. Cigna TTK Health Insurance would cover the balance Rs. 14,400.