The offer is conditional that Hercules must own 90% or more of the company at the close of offer.
Hercules said the offer price of $1.20 per share is final and does not intend to revise it.
In June, Hercules launched a voluntary conditional cash offer to delist Hupsteel from the mainboard of the Singapore Exchange.
The offer price represented a premium of 51.9% over the last transacted price of 79 cents on June 27, being the last full market day immediately prior to the offer announcement.
On Aug 2, Asian Corporate Advisors, the Independent Financial Advisors (IFAs) for the offer, recommended to the board that the financial terms of the offer was "fair and reasonable".
Shares of Hupsteel had closed 1 cent higher at $1.19 on Friday.