IPO difficulties

It's tough to IPO my state corporations. With no tax, the market value increases too quickly. By the time it reaches $300B, the corporation is only upgraded to around 135-140 and cannot produce enough profit to reach 40 P/E.

Are there optimum settings to IPO a corporation that I'm missing?

Try this strategy:
1. Let the corps upgraded until max upgrade 200 (quality&proces)
2. Wait until your corps get around 400B-500B Market value. No tax will speed up this process like you did.
3. Deactivate automatic product sales for your corp (go to Automation Settings -> Existing Corp). You need to stock up the prodcut.
4. Wait maybe i think 12 month in game is enough for most corp.
5. After that you sell all the product at once when the market is red. Don't forget to turn on again automatic sales.
6. Your corps should be ready to IPO in 1-3 month in game.

I use this often in my country and works pretty good. But its quite hard to IPO for corp that produce surplus product.

Thank you, I will give this a try.