The reason why Marconi took out such a large loan was that when listening to seniors they discussed how improving the early game with small bonuses add up in the future.
Just like student debt, or a video game. By monopolizing the early game, it provides a large advantage in the late game expanding his potential and creating more future value and increasing his investment value. By showing how he could liquidate that much currency, he could take better loans at lower interest rates.
Marconi isn't a merchant, nor does he have any economic sense since he is a sixth grader, but he did read a book about economics from the south sea bubble and how a man named Mr. blunt became rich. A good way would have been to run his own high risk interest rate loans and compete with the cutthroat competition and meet shark, but Marconi decides to invest in himself and maybe his friends. A fun way he thought he could sell these credits was through a funny way in which Mr. John Blunt sold his stock in the south seas, artificially raising the price.
So Marconi came up with a scheme first he went to Lazlo the winner of the competition and a social butterfly.
"Hey Lazlo", approached Marconi.
"Who are you?", asked Lazlo. "
I'm Marconi", he introduced himself, and "I need your help, Edgar sent me. He's got a racket going on and he's willing to pay you 12 academic credits at the end of the month".
"Nice academic credits, but show me you have the money before you talk", while Lazlo responds Marconi pulls out a wad of paper academic credits.
"Don't worry, I got it", Marconi shows him.
"What do you need me to do?" Lazlo asks. "Spread the word there's an auction at the playground and people can enter with a 2 credit fee", said Marconi.
"Is this reliable", lazlo asked. It sure is Marconi responded.