17-03-2017 12:26 PM
Reinsurance is when an insurer transfers a part of its risk to a reinsurer by paying a reinsurance premium. Generally most insurers will restrict the risk on their books to some limit and pass on the rest to a reinsurer.
Co-insurance is when two or more insurers come together to share the risk in some proportion.
The impact of reinsurance and coinsurance is similar since both reduce the ultimate risk carried by the insurer but the dynamics and competitive impact are different.