If Big Money is indeed the secret source of Q, then what better letter?
Consider that in the early 1900s Millionaires ($M) were Big Money, and then into the end of the century Billionaires ($B) were Big Money, and now we’ve got people close to being Trillionaires ($T).
What’s next? Quadrillionaires. Yes, $Q. Truly Big Money, with a capital Q.