Thai shopping mall owner Siam Piwat Co. is moving closer to what would be the country’s biggest initial public offering in about two years, according to people with knowledge of the matter.

The Bangkok-based company is asking international banks to submit proposals for a potential first-time share sale that may take place before the end of this year, the people said, asking not to be identified as the process is private. Siam Piwat is aiming to raise $500 million to $750 million in the IPO, they said, adding that deliberations are ongoing and it could decide not to list.