It's a mystery

I am trying to figure something out and I have no clue at all. I started a game in sins of a solar empire trinity about a week ago and up to now have just over 15 hours in and its winding down. I am in the lead and there are 9 other computer players(8 are normal difficulty and 1 hard). About 13.5 hours in, the hard computer player went from having 57,000 credits(about 2% of total) in the bank to over 338,000,000,000(over 99%) in less than 2 hours and the player with the second most is me with around 2,500,000. I checked credits from planet income, trade ships, other sources, selling other players and on black market and none of these went up for them.

It's not really a big issue, but I want to figure it out so that I can get those kind of credits. Does anyone have an idea or clue?