Recently we changed the marketplace to always have an availability of 525k credits on the left side of the market and 425k cash on the right side to stabilize the economy.

We have further modified it so that it maintains just 5 on each side, refilling at the rate of 1 a minute any time it dips below 5.  This means that it is there to help stabilize the economy, but you can't pull or push too much money at any given time.

In practice:

If you need 500 credits from the left side, it will take you a lot of clicks over a lot of time.

If you need 200 million from the right side, it will take you a lot of clicks over a lot of time.