Samick is a Korean manufacturer founded in 1958, though in 1992 it opened a factory in Indonesia and most if not all of the chordophones are now made there. There is also some manufacturing done in mainland China but I'm not sure if Samick has any part of the ownership of the factories making these instrument for them.

It started as a piano manufacturer but fairly quickly added guitars to the catalogue, with an American called Greg Bennett as the chief designer. In the beginning they just made Guitars, but over the years they have added Mandolins, Banjos, and in the 2000's Ukuleles to the range and branded them Samick Greg Bennett. When they were making Samick Greg Bennett Ukuleles, they only made Concerts in 3 different wood choices and a Baritone in the range, but in 2013 they stopped branding the Ukuleles, Mandolins and Banjos with the Greg Bennett name. 

They are still making Ukuleles though, just branded Samick with a large S on the headstock. The new Samick range has a different oval sound hole and comes as Soprano, Concert, Tenor and Baritone, (though no wood choices). They also make Guitalele/Terz Guitar size, (475mm - 18½in scale), solid body "Mini Guitars" under the Samick branding. 

They have added another range of Ukuleles to their catalogue too, It's called Moana, (which is apparently the Hawaiian word for the sea?) and comes as Soprano, Concert, Tenor and Baritone, in a number of laminate or wood options including a deluxe solid koa range. It is possible they are phasing out Samick Ukuleles for this branding? 

Samick also do OEM for a number of major US Guitar makers, most famously for Gibson's Epiphone range, (for whom they make all of the Ukulele models), and in 2014 they acquired and are using the Silvertone brand name. There are a number of other brand names they own and use, Alesis, Arturia, Vanesse are some but I have only seen these used outside of the sphere of Ukuleles.

They were a partner in and made Hondo Guitars until 1989.