The story
Partly imitative, also influenced by burble. Compare Middle Dutch bobbe (“bubble”) > Dutch bubbel (“bubble”), Low German bubbel (“bubble”), Danish boble (“bubble”), Swedish bubbla (“bubble”). The word was first used in its economic sense in association with the collapse of the South Sea Company in 1720, based on the metaphor of an inflated soap bubble bursting.
Etymology from Wiktionary, CC BY-SA 4.0.