Orbcomm Inc. added 28,000 net billable subscribers in the 2007 second quarter, the company announced July 5. The additions give Orbcomm a total subscriber base of more than 278,000 at the end of June, an increase of 11 percent from the end of March.

Orbcomm maintained its annual guidance estimate that it will add 150,000 to 170,000 net additions during 2007.