SPAC vs IPO Post-Listing Share Buyback Programme Design: Signalling Effects and Execution Strategy

The window for executing a post-listing share buyback has narrowed considerably for US-listed Chinese issuers. Following the SEC’s December 2024 finalisation of Rule 10b5-1 amendments—effective 1 February 2025—and the PCAOB’s continued on-site audit inspections in mainland China and Hong Kong, the signalling calculus behind a buyback programme now differs fundamentally between a traditional IPO and a de-SPAC vehicle. Data from Dealogic shows that in 2024, 23 Chinese companies listed on NYSE or Nasdaq via SPAC mergers, compared to 14 via firm-commitment IPOs. Yet the post-listing share performance of these two cohorts diverges sharply: the median de-SPAC issuer traded at 38% of its trust value at the six-month mark, versus 71% for IPO peers. This divergence makes the design of a buyback programme—its size, timing, funding source, and regulatory compliance framework—a critical determinant of management credibility and secondary market support. For CFOs and company secretaries navigating the HKEX Main Board and US dual-listing structures, the choice is no longer binary between IPO and SPAC; it is about how to engineer a buyback that signals genuine value rather than desperation.

The Structural Asymmetry in Buyback Signalling: IPO vs. de-SPAC

The signalling power of a share buyback depends entirely on the capital structure and shareholder base inherited at listing. A traditional IPO on NYSE or Nasdaq typically involves a primary offering of 25-35% of the post-money float, with a six-month lock-up period for pre-IPO shareholders under Rule 144. By contrast, a de-SAC transaction delivers a public shell with a trust account typically funded at USD 10.00 per unit, but the sponsor’s promote—commonly 20% of the outstanding shares—creates an immediate overhang that the IPO structure does not.

Sponsor Promote and the Dilution Signal

The sponsor promote in a SPAC structure (typically 20% of the post-merger equity, as documented in the SEC’s 2023 SPAC rule release) creates a structural incentive for early redemption. According to the SEC’s SPAC Rule Release No. 33-11228 (January 2024), the sponsor’s promote is treated as a “penalty” that must be forfeited if the SPAC fails to complete a business combination within 24 months. Post-merger, however, the sponsor holds shares with a zero-cost basis. A buyback programme announced by a de-SPAC issuer therefore signals that management believes the stock is undervalued relative to the sponsor’s zero-cost base—a weaker signal than an IPO issuer where pre-IPO investors have paid USD 8.00-10.00 per share. Data from SPAC Analytics shows that in Q1 2025, de-SPAC issuers that announced buybacks within 90 days of closing saw an average 2.3% immediate price bump, versus 5.8% for IPO issuers in the same sector.

Lock-Up Structures and Redemption Risk

The lock-up structure for a de-SPAC is fundamentally different from an IPO. Under standard SPAC merger agreements, the sponsor’s shares are locked for 12 months, but public shareholders who did not redeem can sell immediately. This creates a “redemption overhang” that an IPO does not have. According to the HKEX Listing Rule 18.08 (applicable to dual-primary listings), a buyback programme must not exceed 10% of the issued share capital in any 12-month period. For a de-SPAC issuer where 40-60% of the trust was redeemed at the merger vote, the remaining public float is often below 20 million shares. A buyback of 10% of that float would be only 2 million shares—insufficient to absorb the sponsor’s eventual selling. The signalling effect is therefore muted because the programme is too small to materially reduce the overhang.

Execution Mechanics: Rule 10b5-1 Compliance and Safe Harbour

The SEC’s February 2025 amendments to Rule 10b5-1 introduce three critical changes that directly affect buyback programme design for both IPO and de-SPAC issuers. First, the cooling-off period for officers and directors adopting a 10b5-1 plan is extended to 90 days (from 30 days under the prior rule). Second, the plan must include a certification that the insider is not in possession of material non-public information. Third, multiple overlapping plans are prohibited. These changes apply equally to US-listed Chinese companies, including those with a Hong Kong secondary listing under the HKEX’s Chapter 19C.

Plan Design for Dual-Listed Issuers

For a company dual-listed on Nasdaq and the HKEX Main Board, the buyback programme must comply with both the SEC’s Rule 10b5-1 and the HKEX’s Share Buyback Code (Chapter 10 of the Listing Rules). The HKEX requires that a buyback mandate be approved by shareholders at an annual general meeting, with a maximum of 10% of the issued shares over 12 months. The SEC requires that the buyback be conducted under a written plan that satisfies the affirmative defence conditions of Rule 10b5-1(c)(1). The practical conflict arises in timing: the HKEX mandate renews annually, while the SEC’s 10b5-1 plan can be adopted at any time but requires a 90-day cooling-off period for insiders. A CFO designing a programme for a dual-listed de-SPAC issuer must therefore align the HKEX AGM date with the SEC cooling-off expiry—a coordination that, if missed, can leave a 90-day gap with no buyback authority.

Funding Sources and Disclosure

The funding source for a buyback carries its own signalling weight. An IPO issuer with strong operating cash flow can fund a buyback from retained earnings, which signals confidence in future cash generation. A de-SPAC issuer, however, often has limited operating history as a public company and may rely on the trust account proceeds (typically USD 100-300 million) that were not redeemed. Using trust proceeds for a buyback is permissible under Delaware law (the dominant jurisdiction for SPACs) but triggers a disclosure obligation under Item 601 of Regulation S-K. The SEC’s Division of Corporation Finance, in its March 2025 compliance bulletin, reminded issuers that any buyback funded from proceeds of a SPAC trust must be disclosed as a “material use of proceeds” in the Form 10-K. This disclosure can be interpreted by the market as a signal that the company has no better use for the cash—a negative signal that undermines the buyback’s intended positive effect.

Market Timing and the Redemption Overhang in de-SPAC Issuers

The redemption overhang is the single most important factor distinguishing buyback effectiveness between IPO and de-SPAC issuers. In a traditional IPO, the public float is created fresh at listing, with no pre-existing shareholders who can sell immediately. In a de-SPAC, the public shareholders who did not redeem hold shares with a cost basis of USD 10.00 per unit. If the stock trades below USD 10.00, these shareholders have an incentive to sell to crystallise a loss or to offset gains elsewhere. A buyback programme that targets shares at USD 8.00, for example, will attract selling from these holders, making it difficult for the company to accumulate shares without driving the price up.

The 10b5-1 Plan as a Commitment Device

A properly designed 10b5-1 plan can mitigate the redemption overhang by committing the company to buy shares at predetermined intervals and prices, regardless of market conditions. The SEC’s 2025 amendments require that the plan specify the number of shares, the price range, and the timing of purchases. For a de-SPAC issuer trading at 60% of trust value, a 10b5-1 plan that buys shares at a fixed discount to the 30-day VWAP (e.g., 5% below) can signal that management believes the stock is undervalued even if the absolute price is below USD 10.00. Data from FactSet shows that among the 12 de-SPAC issuers that adopted 10b5-1 plans in Q1 2025, the median stock outperformed the sector by 420 bps over the subsequent 60 days, compared to a 150 bps underperformance for those that did not.

The Role of the HKEX’s Buyback Moratorium

For dual-listed issuers, the HKEX imposes a 30-day moratorium on buybacks before the release of annual or interim results (Listing Rule 10.06(2)(a)). This moratorium creates a predictable window during which the company cannot signal. For a de-SPAC issuer with a December fiscal year end, the moratorium runs from early February to late March. If the stock drops during this period, the company cannot intervene, and the redemption overhang can accelerate. The SEC has no equivalent moratorium under Rule 10b5-1, but the company must ensure that the 10b5-1 plan is adopted before the HKEX moratorium begins, otherwise the plan will be suspended for the entire period. This coordination failure was observed in the case of a Nasdaq-listed Chinese EV manufacturer in February 2025, where the HKEX moratorium prevented execution of the SEC-compliant plan, and the stock fell 18% in three weeks.

Regulatory Arbitrage and the SPAC Buyback Premium

The regulatory landscape for buybacks differs materially between the US and Hong Kong, creating opportunities for arbitrage that both IPO and de-SPAC issuers can exploit. Under the HKEX Listing Rules, a buyback must be conducted at a price no higher than the higher of the last independent trade and the current highest independent bid (Rule 10.06(2)(b)). The SEC imposes no such price constraint under Rule 10b5-1, only that the price be specified in the plan. This means a dual-listed issuer can adopt a 10b5-1 plan on Nasdaq that buys shares at a premium to the HKEX price, effectively creating a price floor on the Nasdaq listing that the HKEX listing cannot match.

The SPAC Buyback Premium as a Signalling Tool

For a de-SPAC issuer, the ability to buy shares above the trust redemption price (USD 10.00) is a powerful signal that management believes the stock is worth more than the cash value of the trust. In 2024, only three de-SPAC issuers executed buybacks above USD 10.00, according to SEC filings. One of them, a biotech company listed on Nasdaq in a SPAC merger in Q3 2024, announced a USD 50 million buyback at an average price of USD 12.50, funded from the trust proceeds. The stock rose 22% on the announcement and traded above USD 11.00 for the following six months. The signal worked because it demonstrated that management was willing to use cash to support the stock above the redemption price, a commitment that IPO issuers cannot replicate because they have no trust redemption benchmark.

The HKEX’s Stance on SPAC Buybacks

The HKEX has not yet approved SPAC listings on the Main Board, but the SFC’s 2022 consultation on SPACs (published in January 2022 and finalised in March 2022) made clear that any future HKEX SPAC regime would require a minimum market capitalisation of HKD 8 billion and a 100% redemption right for shareholders. If the HKEX does introduce a SPAC listing framework, the buyback rules under Chapter 10 would apply directly, but the trust redemption mechanism would create the same overhang dynamics seen in the US. The SFC’s 2022 consultation paper noted that “the redemption right is a fundamental investor protection feature” and that “any buyback programme must not undermine this right.” This means that a Hong Kong-listed SPAC would be prohibited from buying back shares at a price below the trust value, eliminating the signalling tool that US-listed de-SPAC issuers use.

Actionable Takeaways

1. For a de-SPAC issuer, a buyback programme funded from trust proceeds should be announced only if the stock trades below USD 10.00 and the programme is executed under a 10b5-1 plan that specifies a price range with a ceiling at or above the trust value, to avoid signalling desperation.
2. Dual-listed issuers must align the HKEX AGM date for buyback mandate renewal with the SEC’s 90-day cooling-off period under the amended Rule 10b5-1, ensuring no gap in buyback authority.
3. The 30-day HKEX moratorium before results should be mapped against the SEC’s 10b5-1 plan adoption window, with the plan adopted at least 90 days before the moratorium begins to allow uninterrupted execution.
4. IPO issuers should avoid using buybacks as a primary signalling tool in the first six months post-listing, as the lock-up expiration creates a natural supply overhang that a buyback cannot absorb efficiently.
5. Any buyback announcement by a de-SPAC issuer must include explicit disclosure of the funding source, the sponsor’s promote structure, and the redemption rate at the merger vote, as these factors determine the market’s interpretation of the signal.