X0306 4 2012-10-29 0 0001372375 Millennial Media Inc. MM 0001545621 Brandenburg John Christopher C/O MILLENNIAL MEDIA, INC. 2400 BOSTON STREET, SUITE 201 BALTIMORE MD 21224 0 1 0 0 EVP, Chief Technology Officer Common Stock 2012-10-29 4 S 0 895672 13.4425 D 3955540 D Common Stock 629235 I By GRAT This total includes 20,765 shares previously held by The John Christopher Brandenburg 2010 Grantor Retained Annuity Trust that were transferred to the reporting person on May 1, 2012 and are now owned directly by the reporting person. This total excludes the 20,765 shares transferred to the reporting person as described in footnote 1. The shares are held by The John Christopher Brandenburg 2010 Grantor Retained Annuity Trust, of which the reporting person is the trustee. /s/ Brian F. Leaf, Attorney-in-fact 2012-10-29