Premiums for almost all of Louisiana Citizens Property Insurance Corp.’s commercial customers will increase an average of 2.3 percent beginning in February, under a proposed rate filing.

But the 307 customers whose properties lie below the Gulf Intracoastal Waterway will see rates drop by 17.5 percent, said Citizens Chief Financial Officer Steve Cottrell. The average policyholder there will see annual rates drop to $4,764, a savings of $1,011.

The main reason is that the cost of reinsurance, the insurance that insurers buy to protect themselves from excessive claims, has fallen, Cottrell said. The reinsurance savings are greater in coastal areas, where the risk of hurricane losses is greater and reinsurance costs are higher.

Four parishes account for almost all of the policies below the Intracoastal: Lafourche, Plaquemines, Terrebonne and Jefferson. Citizens cut commercial rates in those areas an average of 23.8 percent for 2014.

Citizens has 4,023 commercial policies above the Gulf Intracoastal Waterway. Roughly half of those properties lie in Orleans and Jefferson parishes, according to the rate filing. The average premium above the Intracoastal will increase 2.3 percent, or $109, to $4,846.

Taking into account those receiving increases and the those with decreases, overall commercial premiums will be reduced by 0.2 percent, Cottrell said. It’s the second year in a row that Citizens has reduced overall commercial rates.

Citizens’ board of directors voted Thursday to approve the rate filing.

“You don’t see rate decreases in Louisiana on any type of insurance,” board member Gene Galligan said.

Galligan said he initially was against the rate decrease because he doesn’t want to see Citizens competing with private companies.

But Citizens has done such a good job reducing its reinsurance costs that the state-backed insurer has no choice, he said.

Citizens is the state’s property insurer of last resort and covers properties private insurance companies will not. In most cases, state law requires Citizens to charge more than private insurers.