Don't know the HN article but here's my own list:

AEG = TTI

Black and Decker = Stanley (Stanley Black&Decker, SBD)

Bosch = {}

Craftsman = Stanley

Dewalt = Stanley

Hikoki = Hitachi

Irwin = Stanley

Kango = TTI

Klein = {}

Lenox = Stanley

Makita = {}

Metabo = Hitachi

Milwaukee = TTI

Porter-Cable = Stanley

Ryobi = TTI

The empty-set ownership symbol {} means not owned by anyone else.