From the Cambridge English Corpus When Actual physical cash is complementary with human cash in output, returns on as well as demand from customers for competencies rise bubble up, intumesce - shift upwards in bubbles, as through the result of heating; also utilized metaphorically; "Gases bubbled up from the earth"; https://open.spotify.com/track/34R2ybXWvR8moYMvTNxLRZ?si=69c44df25f7d4fd5