Taiwan-based biotechnology firm SL Bio Ltd. has filed a Form F-4 with the U.S. Securities and Exchange Commission to advance its merger with Horizon Space Acquisition II Corp. ( HSPT ) , a deal that would take the company public via a SPAC rather than a traditional IPO.

Under the proposed transaction, SL Bio will acquire Horizon Space Acquisition II ( HSPT ) at an implied equity valuation of about $5.7 billion. The combined company will operate as SL Science Holding Limited and trade under the ticker SLBT, with SL Bio serving as the primary operating business and HSPT as the publicly listed acquisition vehicle.

While Horizon Space Acquisition II ( HSPT ) is a relatively small SPAC, the deal highlights the continued use of SPAC mergers as an alternative path to U.S. public markets—particularly for capital-intensive sectors such as biotechnology, where long development timelines and regulatory hurdles can complicate conventional IPOs.

The transaction remains subject to regulatory review and shareholder approvals. If completed, it would give U.S. investors direct exposure to SL Bio through a publicly listed holding company.

An Alternative Public Listing Path

The proposed combination reflects a broader trend. Emerging companies are turning to SPAC transactions as an alternative to conventional IPOs. Currently, public market conditions for early-stage and research-focused firms remain selective. But reverse mergers continue to be used to facilitate access to long-term capital, public market visibility, and institutional investor participation.

SL Bio is focused on advanced biotechnology research, including cellular and gene therapy technologies. The company is developing immunotherapies for high-need oncology indications, including blood cancers, pancreatic cancer, and brain tumors.

SL Bio is also pursuing exosome-based regenerative technologies, which have potential applications across both medical therapeutics and consumer health products.

The companies have indicated that the public listing of the combined entity could take place in early 2026, subject to customary closing conditions and prevailing market dynamics.

Price Action:

Shares of Horizon Space Acquisition II Corp ( HSPT ) closed at $10.55 on Thursday.

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