One Share, Five Months

On 14 August 2026, BASE (4477) filed five corrections to its own buyback reports. They cover five consecutive monthly reporting periods — 13 to 28 February, then March, April, May and June — and each of the five changes the same figure by one share.

Under ３【保有状況】, the holding position at the end of the reporting month, （訂正前） reads 保有自己株式数 2,774,286 and （訂正後） reads 2,774,285. That pair appears in all five documents, against five different month-end dates.

The 自己株券買付状況報告書 is filed monthly by a company buying back its own shares, and the holding line is a running position rather than a monthly flow. February's figure carries into March, March's into April. One share wrong in February is one share wrong in every month after it, until the month it is corrected.

That is what five documents filed on one day are for. The originals went in on 13 March, 14 April, 15 May, 15 June and 13 July; the corrections all went in on 14 August, together.

The reason line is the same in all five: 記載事項の一部に誤りがありましたので — there was an error in part of the recorded matter — followed by これを訂正するため. None of the five says what the error was. The pair below says it, one digit at a time.

The issued-share figure moves too, but not as a correction. February's documents print 発行済株式総数 117,905,657; the four later months print 117,931,657, in both the （訂正前） and （訂正後） blocks. The company issued 26,000 shares somewhere between the end of February and the end of March, and that is not what is being corrected.

The sixth correction in the week is a different kind. Seika (8061) filed one on the same 14 August against its June report, and it corrects two sections rather than one.

Under ２【処理状況】, the disposal position, （修正前） reads 該当事項はありません — there is no applicable item — and （修正後） carries a table: two disposal dates in June, 17 and 26, under a heading naming a share-delivery trust and the exercise of stock options, totalling 86,663 shares.

Under ３【保有状況】 the same document moves 保有自己株式数 from 1,205,216 to 1,118,553. Subtracting one from the other gives 86,663, the same figure the new table totals. The two corrections move together: the disposal section stood at 該当事項はありません, and the holding line stood at the level it had before those two dates.

Seika's blocks are labelled 修正前 and 修正後. BASE's are labelled 訂正前 and 訂正後. Same form, same document type, same week, and the word for the block before the change is not the same word.

Six corrections, then, and two shapes. Five say a number was one too high. One says a section that reported nothing should have reported two disposals, and the number that depended on it was too high by their total.

The second shape is the one a reader would expect a correction to have: something missing, now supplied, with the consequence carried through to the figure it feeds. The first shape is the one the monthly form produces on its own. A running total that is wrong stays wrong at the same size for as long as nobody restates it, and restating it means filing once for every month it stood.

On the counts. The six are what EDINET's list returns for document type 230 over 14 to 19 August 2026, pulled on 23 August after the window closed. Five carry BASE's securities code and one Seika's.

The one-share difference and the 86,663 are read from the （訂正前）／（訂正後） and （修正前）／（修正後） blocks as printed. The subtraction that matches Seika's two corrections to each other is mine; neither document prints the difference.

What this does not show: whether BASE's five are the whole of the correction. The reports before February are outside this window and were not read, and if the same share was miscounted earlier, the corrections for those months would sit on an earlier list.

One share, five times, on one day.