Some manufacturers merged or changed hands over the years which added to the confusion, sometime merging with another maker, only to pick up their name later. Listed below are the major manufacturers, known badges and suspected badges to the best of my knowledge in written and list form to make it easy to find out !
In some cases a manufacturer would farm out production to various manufacturers, making it still more difficult to know who made the guitar in your hands. In some cases I won't know because the badge you have may be extremely rare and virtually unknown to even seasoned collectors.
The source dating code is an element of standardization that is administered by the Electronics Industries Alliance (EIA).
The EIA assigns each manufacturer a three-digit code (there are some with one, two or four digits).
EKO was at the forefront, and within 2 years they were shipping over 10,000 electric guitars to USA per year.