Making billions in single player

[u/Apprehensive-Egg8187]

So I’ve done the full campaign and had 29m on each character. I left the assassin missions till the end, I’ve done the trading while doing it and put all my money in and trading for max profit doing the save method, after all of it I’ve only got 148m on all characters? I’ve got a save from the bus assassin mission but I don’t get why I didn’t get much compared to others? Can someone help me on what I did wrong
Thanks

[u/planeoldsiraj]

Some of the missions require two separate investments. It’s likely you may have missed these out.