Aetna, one of the nation's largest health insurers, has pulled out of its sixth Obamacare insurance exchange.

The company announced this week that it will not join the state-based exchange in New Jersey, as it reviews its participation in the Affordable Care Act. It will continue to serve employers and offer plans to individuals outside of the exchange in the Garden State, where it has 1.1 million customers.

Only 2,600 of those customers, however, buy individual plans through Aetna.

"We are not, and have not been a large player with a mature, robust presence to begin with in the individual market in New Jersey," a spokeswoman said.

Have questions on Obamacare? Tune in to CNNMoney's live Facebook chat next Friday

Neither Aetna (AET) nor Conventry Health Plans, which it acquired earlier this year, will be represented on exchanges in Georgia, Maryland, Connecticut, New York, West Virginia or New Jersey. Aetna remains on the Texas exchange, while Conventry will participate on the Ohio exchange. The company is reviewing its filings in other states.

Aetna is one of several large insurers that will have limited involvement in the exchanges, at least in 2014. UnitedHealthcare (UNH) and Cigna (CI) are also participating in only a handful of exchanges.

Aetna, however, won't rule out participating in the exchanges in future years.

"As we have consistently stated, we are taking a measured, multi-year approach to exchanges," the spokeswoman said.