"Early forms of the electric bass guitar were brought to market by Vivi-Tone of Kalamazoo, MI, in the early 1930s, Rickenbacker of Los Angeles in 1935, Audiovox of Seattle, in 1936, Vega of Boston, MA, in 1939, and Regal of Chicago, in 1939."
"The modern full-scale fretted solid body electric bass guitar was introduced by Leo Fender and was first marketed as the Fender Precision Bass in late 1951. The instrument was introduced to meet the needs of musicians playing the bass part in small dance bands in the United States."
Quotes source: "Electric bass guitar [bass guitar]" in The Grove Dictionary of American Music, 2nd edition, ed. by Charles Hiroshi Garrett [online]. Accessed April 6, 2017.