The Valco Manufacturing Company was established in the 1930s by the former owners of the National Dobro Company; Victor Smith, Al Frost, and Louis Dopyera. The company name was a combination of their initials (V.A.L.) plus "co" for company. Valco was a large scale producer of budget instruments including: acoustic guitars, metal-bodied resonator guitars, electric lap steel guitars, and vacuum tube amplifiers under various house brand names including Supro, Airline, Oahu, Melofonic and National. They also made amplifiers for several other companies such as Gretsch, Harmony, and Kay. In the 1950s they started making solid body electric guitars. The Valco company merged with Kay Musical Instrument Company in 1967, but the new company soon ran into financial problems and went out of business in 1968.
Source: Supro catalogs 1948 - 1968