FedEx Corp forecast third-quarter profit below analysts' expectations, sending the package delivery giant's shares down 3.6 percent in premarket trading.

FedEx, considered an economic bellwether because of the scope of its business, also reported second-quarter results in line with its pre-announcement earlier this month.

It forecast third-quarter earnings of 50 cents to 70 cents a share, well below analysts' average estimate of 84 cents, according to Thomson Reuters I/B/E/S.

The company forecast profit for the full fiscal year of $3.45 to $3.75 per share, compared with analysts' forecast of $3.46.

For the second quarter, ended Nov 30, FedEx posted a profit of $345 million, or $1.10 per share, down 30 percent from $493 million, or $1.58 per share, a year earlier. The company pre-announced the results on December 7. Before that, it had forecast 65 cents to 95 cents per share.

FedEx said positive economic momentum drove volume growth across all its segments in the second quarter.

Its shares were down 3.6 percent to $86.72 in premarket trading.

(Reporting by Helen Chernikoff; editing by John Wallace)