A 1-to-0.5 Merger Ratio Does Not Tell You Who Gets the Better Deal
Translate a merger ratio into exchanged shares and post-merger ownership, then compare valuation assumptions and shareholder protections. Distinguish rule announcements from effective dates.
A merger ratio shows how many shares in one company are exchanged for shares in another. The size of the ratio alone cannot establish whether terms are favorable; compare both companies' assessed per-share values and the value of the combined business.
State explicitly which company's share is the reference
Using one share of surviving company A as the reference, write out how many A shares are delivered for each share of absorbed company B. If assessed per-share values are KRW 20,000 for A and KRW 10,000 for B, a ratio of 0.5 A shares for each B share can be considered. This does not mean B's total company value is half of A's, because their issued share counts differ. Fractional-share treatment, treasury shares, cross-holdings, and cash payments can further change the actual number of new shares.
Translate exchanged shares into post-merger ownership
Multiplying B's eligible share count by the exchange ratio gives a simple calculation of the new shares A must deliver. Add these to A's existing shares, then calculate each shareholder's proportion of the combined company. Next estimate the merged company's earnings and borrowings on a consistent basis. Simply adding the two companies' net income can miss integration costs, elimination of intercompany transactions, and acquisition accounting effects. Read synergy claims concretely: which business's revenue or costs will change, and by how much?
Check assumptions and applicability dates as well as valuation formulas
External valuations and board opinions raise questions about cash flow assumptions, peers, discount rates, and interests involved. Obtaining a valuation does not guarantee the best terms for every shareholder. The Financial Services Commission's August 20, 2026 materials on fair value announce passage of legislation and explain the planned implementation schedule following promulgation. Do not turn the announcement date into an immediate effective date; check the laws and transitional provisions applicable at the transaction date. Also verify the timetable for notices of dissent and appraisal rights in the merger disclosure itself. A change in your assessment of the other company's value may alter your view of the ratio's fairness. Compare both companies using the same analysis date and accounting scope, rather than updating the earnings used to value one while leaving the other's historical estimates unchanged.
Worked example
Hypothetical example: A has 10 million existing shares and B has 4 million eligible shares. If each B share receives 0.5 A shares, A issues 2 million new shares. The post-merger total is 12 million, and B's former shareholders collectively hold 200/1,200=approximately 16.67%. This does not mean B is worth half of A; it means those shareholders receive approximately one-sixth of the combined company under these terms.
What to check
- Write out the exchange ratio's numerator and reference company in words.
- Check the eligible share count and fractional-share terms.
- Calculate post-merger shares and ownership percentages.
- Match valuation assumptions and regulatory effective dates to the transaction date.
Sources and primary materials
This is educational material about research methods. For an actual company decision, verify the filings and primary sources for the relevant period.