Why doesn’t anti-matter anti-gravitate?

Flying pig.[Image: clipartfest.com]

Why aren’t there any particles that fall up in the gravitational field of Earth? It would be so handy – If I had to move the couch, rather than waiting for the husband to flex his muscles, I’d just tie an anti-gravitating weight to it and the couch would float to the other side of the room.

Newton’s law of gravity and Coulomb’s law for the electric force