1922, in golf, from up (adv.) + swing (n.). Sense in economics is attested from 1934.
Entries linking to upswing
up adv.
Old English up, uppe, from Proto-Germanic *upp- "up" (source also of Old Frisian, Old Saxon up "up, upward," Old Norse upp; Danish, Dutch op; Old High German uf, German auf "up"; Gothic iup "up, upward," uf "on, upon, under;" Old High German oba, German ob "over, above, on, upon"), from PIE root *upo "under," also "up from under," hence also "over."
As a preposition, "to a higher place" from c. 1500; also "along, through" (1510s), "toward" (1590s). Often used elliptically for go up, come up, rise up, etc. Up the river "in jail" first recorded 1891, originally in reference to Sing Sing, which is up the Hudson from New York City. To drive someone up the wall (1951) is from the notion of the behavior of lunatics or caged animals. Insulting retort up yours (scil. ass) is attested by late 19c.
swing n.
Old English swinge "stroke, blow; chastisement," from swing (v.). Meaning "suspended seat on ropes" is from 1680s. Meaning "shift of public opinion" is from 1899. The meaning "variety of big dance-band music with a swinging rhythm" is first recorded 1933, though the sense has been traced back to 1888; its heyday was from mid-30s to mid-40s. Phrase in full swing "in total effect or operation" (1560s) perhaps is from bell-ringing. The backyard or playground swing-set is from 1951.