X0303 4 2008-10-07 0 0001136655 ARBINET THEXCHANGE INC ARBX 0001265181 SINGER KAREN 212 VACCARO DRIVE CRESSKILL NJ 07626 0 0 1 0 Common Stock 2008-10-07 4 P 0 2899 2.32 A 4134508 I As the trustee of the Singer Children's Management Trust The reporting person disclaims beneficial ownership of these securities except to the extent of her pecuniary interest therein. This filing shall not be deemed an admission that the reporting person is, for purposes of Section 16 of the Act or otherwise, the beneficial owner of any equity securities covered by this filing. /s/ David J. Hoyt Attorney-in-fact 2008-10-08