You can raise market value by buying the maximum amount of supplies, which is 120 months worth. That almost immediately increases the asset value. The market value of a profitable corp is influenced considerably by the asset value. That means the market value will increase when you increase the asset value, slowly.
It also helps to keep as much cash as possible in the corp. That includes keeping profit transfer at zero.
If you get desperate to increase market value, you could consider buying the highest quality supplies. That's tricky because it will result in lower profits, which eventually will hurt your market value. So hopefully you'll IPO before the rolling average profit makes a big decline. Then after the IPO, you can reduce the quality.
There is an amusing loophole for increasing the market value substantially. Some of us don't post loopholes on the forums because that tends to get them nerfed. Here is a clue
I have some corporations that could go public. It is possible and we have recently increased the price range of some products. These corporations become more profitable and their value increases.
but at the same time, I agree that the 500B limit is too high.
I will decrease it within an hour or two. It will go to 400B for now.
Has this change been implemented yet?
I have a number of corps between 400-500B but they are still marked as below the market value for an IPO.
"I will decrease it within an hour or two"
This still doesn't appear to have been implemented.