Resonac Holdings (TSE Prime: 4004) is pressing ahead with the carve-out of its petrochemical business, and the same disclosure that updates the spin-off timetable comes paired with a separate notice that automatically re-prices the group's outstanding convertible bonds.
The carve-out
On July 6, Resonac laid out updated plans to spin off Culasus Chemical, the wholly owned subsidiary that makes ethylene, propylene and other basic petrochemicals. The restructuring plan cleared certification under Japan's Industrial Competitiveness Enhancement Act on June 12, 2026, and now goes to Resonac's board for a final vote in late August. If approved, Resonac will distribute more than 80% of its Culasus shares to its own shareholders as an in-kind dividend, one Culasus share for every Resonac share held. Culasus, which posted ¥300.3bn in revenue and ¥4.7bn in core operating income for the year to December 2025, plans a direct listing on the Tokyo Stock Exchange's Standard Market on September 29, 2026, with no public offering ahead of the listing. Once the distribution goes through, Resonac's remaining stake in Culasus falls below 20%, taking the unit off its consolidated books entirely.
| Date | Event |
|---|---|
| Late August 2026 | Resonac board vote on executing the spin-off |
| Sept 28, 2026 (Mon) | Last day Resonac shares trade with dividend rights attached |
| Sept 29, 2026 (Tue) | Resonac shares go ex-dividend; Culasus Chemical lists on the TSE Standard Market |
| Sept 30, 2026 (Wed) | Record date for the share distribution |
| Oct 1, 2026 (Thu) | Distribution takes effect; convertible bond conversion-price adjustment becomes effective retroactively |
The bond math
That timetable feeds directly into Resonac's outstanding Euro-yen convertible bonds due 2028. Under the bonds' terms, the spin-off automatically triggers a conversion-price adjustment once Resonac's board approves it. Resonac has hired Conv-Ex Advisors Limited as an independent financial adviser on how to apply the formula. The new conversion price is calculated by multiplying the old price by Resonac's average trading price over a five-day window, divided by the combined average trading prices of Resonac and Culasus over that same window. That evaluation period runs from September 29 to October 5, 2026, the first five Tokyo Stock Exchange trading days on which both stocks have quoted prices. The adjustment itself takes effect retroactively from October 1, 2026, the same day Culasus shares land in shareholders' accounts.
What isn't settled yet
The size of the cut to the conversion price is not fixed today. It depends entirely on how the market prices Resonac against Culasus during that five-day window in late September, a stretch of trading that has not happened yet. Resonac also says the accounting impact of the spin-off on its consolidated results is still under review and has not been finalized. The next hard date on the calendar is Resonac's board meeting in late August, when directors vote on whether to execute the spin-off at all.