Four Chinese mainland firms are ‌looking to raise up to a combined HK$14.35 billion ($1.83 billion) via separate listings in the Hong Kong Special Administrative Region, with automation equipment maker RoboTechnik accounting for the largest portion, ​exchange filings showed on Monday.

The offerings come as Hong Kong's ​market for initial public offerings and secondary listings continues ⁠to strengthen. Deals have raised about $45.8 billion so far this year, ​compared with $24 billion in the same period last year, LSEG data showed.

RoboTechnik ​Intelligent Technology is offering 11.9 million H shares at up to HK$436 each, aiming to raise about HK$5.18 billion.

Reuters reported on Friday citing sources that RoboTechnik was ​targeting a Hong Kong listing of about $800 million and planned to ​launch the deal on September 21 with market debut on September 29.

If both a ‌15 percent ⁠offer size adjustment option and the over-allotment option are fully exercised, the total deal could reach HK$6.85 billion at the maximum offer price.

ALSO READ: Ligent Technologies seeks about $723m in HK IPO

The Shenzhen-listed company makes equipment for photovoltaic cell manufacturing and assembly and ​testing systems for ​silicon photonics devices ⁠used in optical interconnects for data centers and AI infrastructure.

Printed circuit board maker Shenzhen Kinwong Electronic and ​materials producer Red Avenue New Materials are seeking to ​raise up ⁠to HK$5.10 billion and HK$3 billion, respectively, through secondary share sales.

Precision motor solutions provider Direct Drive Tech will raise HK$1.08 billion in an ⁠initial public ​offering.

Shares of all four firms are ​expected to start trading on the exchange on September 29.