Notice Regarding Repurchase of Own Shares Through the Off-Auction Own Share Repurchase Trading (ToSTNeT-3) System

February 6, 2026

To whom it may concern

Notice Regarding Repurchase of Own Shares Through the Off-Auction Own Share Repurchase Trading (ToSTNeT-3) System, and Issuance of 1st Series Share Options and 2nd Series Share Options Through a Third Party Allotment (Repurchase of Own Shares Through a Facility Share Repurchase (Accelerated Share Repurchase (“ASR”)))

MITSUI-SOKO HOLDINGS Co., Ltd. (the “Company”) hereby announces that, at its Board of Directors’ meeting held on February 6, 2026, it has resolved on matters concerning repurchase of its own shares (the “Share Repurchase”) in accordance with Article 459, Paragraph 1 of the Companies Act and Article 38 of the Company’s Articles of Incorporation. With respect to the specific methods of such repurchase, the Company has decided that it will implement the Share Repurchase in the form of market purchases on the market operated by the Tokyo Stock Exchange, Inc. (the “Tokyo Stock Exchange”), including purchases through the off-auction own share repurchase trading (“ToSTNeT-3”) system, as described in “I. Share Repurchase” below, and that it will also implement part of the Share Repurchase through ASR (for details, please refer to “4. Facility Share Repurchase (ASR)” under “I. Share Repurchase” below).

In addition, in connection with executing part of the Share Repurchase through ASR, at its Board of Directors’ meeting held on the same day, the Company has resolved to issue its 1st series share options (the “ASR Share Options With a Fixed Amount of Investment”) and 2nd series share options (the “ASR Share Options With a Fixed Number of Shares”) (the ASR Share Options With a Fixed Amount of Investment and the ASR Share Options With a Fixed Number of Shares are individually or collectively referred to as the “Share Options”) to SMBC Nikko Securities Inc. (“SMBC Nikko”) through a third party allotment, and, as of today, entered into an agreement with SMBC Nikko regarding the allotment of the Share Options and certain other matters (the “Allotment Agreement”). For details of the resolution on matters concerning the Share Repurchase above, please refer to the “Notice Regarding Repurchase of Own Shares (Repurchase of Own Shares under the Articles of Incorporation Pursuant to Article 459, Paragraph 1 of the Companies Act)” released today.

I. Share Repurchase

1. Purpose of the Share Repurchase

   Under the “Medium-term Management Plan 2022” (covering fiscal years ending March 31, 2023 to March 31, 2027), the Company aims to maintain the high level of capital efficiency. This is based on its policy of executing investments for sustainable growth and paying flexible dividends linked to performance, with an annual dividend payout ratio of 30%.

   After comprehensively considering the Company’s financial position, business plans, and capital market expectations, the Company has decided to implement the Share Repurchase. This decision reflects the judgment that reconsidering the capital allocation toward the final business year of the Medium-term Management Plan and using a portion of those funds to enhance shareholder returns will help increase shareholder value. In addition, the Company has resolved to execute the Share Repurchase to improve capital efficiency and enhance shareholder returns, as it believes that carrying out the Share Repurchase by partially adopting ASR, which enables it to implement the Share Repurchase on a substantial scale immediately, will further solidify its commitment to shareholder returns and ultimately contribute to a cycle of enhancing corporate value.

2. Repurchase Method

   1. Repurchase through the off-auction own share repurchase trading (ToSTNeT-3) system

      The Company will commission the purchase through the Tokyo Stock Exchange’s ToSTNeT-3 system at 8:45AM on February 9, 2026, at the closing price of 3,571 yen (including the final special quote) as of today (February 6, 2026), to implement the Share Repurchase of up to 5,500,000 shares (the “Maximum Number of Shares to be Repurchased”) worth of approximately 19.6 billion yen (“Share Repurchase (ToSTNeT-3)”). This purchase order will be valid only during the relevant trading time.

      SMBC Nikko is scheduled to place a sell order of 2,250,000 shares out of 5,500,000 shares (i.e., the Maximum Number of Shares to be Repurchased) (the shares that are scheduled to be sell ordered by SMBC Nikko is referred to as “Anticipated Number of Shares to be Repurchased (ASR)”) for the Share Repurchase (ToSTNeT-3) (the “Share Repurchase (ASR)”), but the Company and SMBC Nikko will conduct a subsequent adjustment transaction (the “Subsequent Adjustment Transaction”) using the ASR Share Options With a Fixed Amount of Investment or the ASR Share Options With a Fixed Number of Shares so that the Company’s actual purchase price of the shares repurchased from SMBC Nikko will be equal to the average of the volume-weighted average price (“VWAP”) of the Company’s shares in regular-way transactions on the Tokyo Stock Exchange on each trading day (“trading day” means days on which trading sessions are held on the Tokyo Stock Exchange; the same shall apply hereinafter.) during the period from August 3, 2026 to the trading day prior to any exercise date of the Share Options as described below (the “Average VWAP Calculation Period”), multiplied by 100.20% (the “Average VWAP”). The final total repurchase price or the final number of shares repurchased may change due to the Subsequent Adjustment Transaction.

      In addition, upon the Share Repurchase (ASR), SMBC Nikko will borrow shares from the stock lending market, and acquire shares of the Company on the stock market (“Market Purchase Transactions (ASR)”) for a certain period of time (the period during which the Market Purchase Transactions (ASR) are conducted is referred to as the “Market Purchase Period (ASR)”)*for the purpose of returning those borrowed shares. For details, please refer to “4. Facility Share Repurchase (ASR)” below.

      * Market Purchase Transactions (ASR) will be conducted at SMBC Nikko’s discretion, on its own judgment and for its own account, and the Market Purchase Period (ASR) will begin on August 3, 2026 and end on

      January 29, 2027 at the latest. However, if SMBC Nikko notifies the Company of the occurrence of a market disruption date (“market disruption date” means a trading day on which SMBC Nikko reasonably determines that a certain event has occurred under the Allotment Agreement, such as the imposition of trading restrictions on the Company’s shares; the same shall apply hereinafter.) that requires an extension of the exercise period of the Share Options (for details, please refer to below.), the Market Purchase Period (ASR) may be extended by a number of trading days equal to the required number of trading days.

   2. Repurchase through Market Purchases

      Before the Market Purchase Period (ASR), the Company will implement the Share Repurchase through market purchases pursuant to a discretionary transaction agreement (the “Share Repurchase (Market Purchases)”) during the period from February 10, 2026 to July 31, 2026 (the “Market Purchase Period (Share Repurchase)”) to acquire a portion of the Maximum Number of Shares to be Repurchased (i.e., 5,500,000 shares) for which no sell order has been placed, including orders from general shareholders, in the Share Repurchase (ToSTNeT-3).

      (Note) If all the Maximum Number of Shares to be Repurchased are repurchased through the Share Repurchase (ToSTNeT-3), the Share Repurchase (Market Purchases) will not be made. In addition, even if not all the Maximum Number of Shares to be Repurchased are repurchased through the Share Repurchase (ToSTNeT-3), part or all of the Share Repurchase (Market Purchases) may not be made depending on, among other factors, market trends during the Market Purchase Period (Share Repurchase).

3. Details of the repurchase (Share Repurchase (ToSTNeT-3))

   (1)	Type of shares to be repurchased	Common shares of the Company
   (2)	Total number of shares to be repurchased	5,500,000 shares
   		Ratio to total number of issued shares (excluding treasury stock): 7.35%
   (3)	Total repurchase price of shares	19,640,500,000 yen
   (4)	Announcement of repurchase results	The Company will announce the results of the repurchase after the completion of the transaction at 8:45AM on February 9, 2026.

   (Note) 1. The Company will not change the number of shares as noted above. The Company may not repurchase part the shares due to market trends and other reasons.

   (Note) 2. The purchase will be executed for sell orders that correspond to the Maximum Number of Shares to be Repurchased.

   (Reference) Details of the resolution on the Share Repurchase (released on February 6, 2026)

   (1)	Type of shares to be repurchased	Common shares of the Company
   (2)	Total number of shares that may be repurchased	Up to 5,500,000 shares
   		Ratio to total number of issued shares (excluding treasury stock): 7.35%
   (3)	Total repurchase price of shares	Up to 34,000,000,000 yen
   (4)	Period of repurchase	February 9, 2026 through July 31, 2026

   (5)

   Method of repurchase

   Market purchases on the Tokyo Stock Exchange, including repurchase through the off-auction own share repurchase trading (ToSTNeT-3) system

4. Facility Share Repurchase (ASR)

Regarding the Share Repurchase, the Company has concluded that implementing ASR proposed by SMBC Nikko (the Share Repurchase (ASR) and the Share Repurchase through a series of transactions in the Subsequent Adjustment Transaction are hereinafter collectively referred to as the “Scheme”) alongside the Share Repurchase (Market Purchases) is the best option for fulfilling the Company’s need to implement the execution of the Share Repurchase on substantial scale immediately for reasons stated below, and the Company has decided to implement the Share Repurchase through the Share Repurchase (ToSTNeT-3) partially by ASR and through the Share Repurchase (Market Purchases).

Among the methods of repurchasing own shares through market purchases, there are various schemes to repurchase own shares through regular trading sessions, such as the Company placing individual orders, the use of discretionary account transactions by securities companies, and the use of trust companies. When the Company repurchases its own shares at the size anticipated herein through these schemes, given the trading volume of the Company’s shares on the stock market, any market purchase method would require a certain period to complete the Share Repurchase. Unlike the above method, when purchase is entrusted under ToSTNeT-3, the transaction is completed in a day, but depending on the volume of sell orders placed by shareholders, the Company may not be able to repurchase the desired number of own shares.

Although deploying the Scheme for a portion of the Share Repurchase will require procedures related to the issuance of share options, as described below, since SMBC Nikko will place sell orders for the total Anticipated Number of Shares to be Repurchased (ASR) for its own account, the Company will be able to repurchase the total Anticipated Number of Shares to be Repurchased (ASR) with a high probability even if the sell orders placed by general shareholders are not enough. Although it has yet to be determined whether sell orders will actually be placed by SMBC Nikko, SMBC Nikko has confirmed that it would be able to place sell orders for the total Anticipated Number of Shares to be Repurchased (ASR) by borrowing shares from the stock lending market. In addition, the Company believes that the demand and supply of the Company’s shares are also expected to improve as a result of the Market Purchase Transaction (ASR) executed by SMBC Nikko during the Market Purchase Period (ASR), along with the Share Repurchase (Market Purchases).

Please also refer to the information regarding sales by SMBC Nikko, to be published on the Tokyo Stock Exchange website (https://www.jpx.co.jp/markets/public/short-selling/index.html).

Below depicts the Outline of the Scheme:

• On February 9, 2026, the Company will execute the Share Repurchase (ToSTNeT-3) for the Maximum Number of Shares to be Repurchased (5,500,000 shares) worth of the anticipated purchase price (approximately 19.6 billion yen) at a per-share purchase price (3,571 yen) by way of purchase through ToSTNeT-3. In that process, SMBC Nikko will borrow the Company’s shares from the stock lending market to place the sell order of 2,250,000 shares (worth of approximately 8.0 billion yen), out of the 5,500,000 shares above, as the Anticipated Number of Shares to be Repurchased (ASR) in response to the Share Repurchase (ToSTNeT-3).

  This should enable the Company to repurchase the Anticipated Number of Shares to be Repurchased (ASR) in the Share Repurchase (ToSTNeT-3) even if the general shareholders do not place sell orders. Because ToSTNeT-3

  prioritizes general shareholders’ sell orders over those of SMBC Nikko, which is a financial instruments firm, for its own account, if the aggregate amount of sell orders from the general shareholders and the Anticipated Number of Shares to be Repurchased (ASR) exceeds the Maximum Number of Shares to be Repurchased, SMBC Nikko’s sell orders will be executed only for the number of shares excluding such excess amount. Thus, if sell orders from the general shareholders reach the Maximum Number of Shares to be Repurchased, the Share Repurchase (ASR) will not be executed with respect to sell orders from SMBC Nikko, and boththe ASR Share Options With a Fixed Amount of Investment and the ASR Share Options With a Fixed Number of Shares will not be exercised.

• SMBC Nikko has indicated that during the Market Purchase Period (ASR), it will repurchase, at its own discretion, on its own judgment and for its own account, the Company’s shares on the stock market (i.e., Market Purchase Transaction (ASR)) in order to return the number of the Company’s shares it has borrowed and actually sold to the Company in the Share Repurchase (ASR) (such number of shares is hereinafter referred to as the “Number of Shares Sold (Nikko)”).

• With respect to the shares that the Company will repurchase from SMBC Nikko through the Share Repurchase (ASR), the Scheme is designed to ensure that the Company’s actual per-share purchase price will be equal to the simple arithmetic average of the VWAP for all regular-way transaction hours of the Company’s shares on the Tokyo Stock Exchange on each trading day during the Average VWAP Calculation Period, multiplied by 100.20% (i.e., the Average VWAP). Specifically, the Company will allot the ASR Share Options With a Fixed Amount of Investment and the ASR Share Options With a Fixed Number of Shares to SMBC Nikko for the Subsequent Adjustment Transaction, which will be conducted by SMBC Nikko exercising either of the ASR Share Options With a Fixed Amount of Investment or the ASR Share Options With a Fixed Number of Shares on the trading day following the last day of the Market Purchase Period (ASR), depending on the trends of the Average VWAP. Details of the Subsequent Adjustment Transaction are as follows:

  1. When the Average VWAP is higher than the per-share purchase price in the Share Repurchase (ASR) (Subsequent Adjustment Transaction via exercise of the ASR Share Options With a Fixed Amount of Investment)

     • In this case, assuming that SMBC Nikko purchases shares at the Average VWAP in the Market Purchase Transactions (ASR), SMBC Nikko will not be able to purchase the sufficient number of shares to return the borrowed shares even if it uses all the amount it received from the Company in the Share Repurchase (ASR) (the “Received Amount (Nikko)”) (the number of shares that can be purchased under such assumption is hereinafter referred to as the “Number of Purchasable Shares (Average VWAP)”). As such, SMBC Nikko will exercise the ASR Share Options With a Fixed Amount of Investment on the trading day following the last day of the Market Purchase Period (ASR) to purchase the number of shares that falls short. The amount of contribution at the time of exercise of the ASR Share Options With a Fixed Amount of Investment shall be 1 yen, and the number of shares to be issued to SMBC Nikko as a result of the exercise shall be calculated by the following formula:

       Number of shares issued upon exercise of the ASR Share Options With a Fixed Amount of Investment

       = Number of Shares Sold (Nikko) - Number of Purchasable Shares (Average VWAP)

       (Number of Purchasable Shares (Average VWAP) = Received Amount (Nikko) / Average VWAP)

       * The number of shares issued described above represents the number of shares to be issued at an exercise price of 1 yen.

     • The actual number of own shares that the Company will repurchase through the Scheme as a result of the issuance of the Company’s shares due to the exercise of the ASR Share Options With a Fixed Amount of Investment above will be the number of shares purchased by the Company through the ToSTNeT-3 transactions

       less the number of shares issued from the exercise of the ASR Share Options With a Fixed Amount of Investment.

     • Assuming that the aggregate amount of sell orders from the general shareholders and the Anticipated Number of Shares Repurchased (ASR) does not exceed the Maximum Number of Shares Repurchased in the Share Repurchase (ToSTNeT- 3) (all the Anticipated Number of Shares Repurchased (ASR) are sold by the SMBC Nikko for its own account), the result will, by combining the Share Repurchase (ASR) and such Subsequent Adjustment Transaction, be the same as the case where the Company purchases shares at the Average VWAP using approximately 8.0 billion yen, which is the anticipated purchase price in the Anticipated Number of Shares Repurchased (ASR) (this does not take into account the amount of contribution (1 yen) at the time of exercise of the ASR Share Options With a Fixed Amount of Investment). If the aggregate amount of sell orders from the general shareholders and the Anticipated Number of Shares Repurchased (ASR) exceeds the Maximum Number of Shares Repurchased, the number of the Company’s shares that SMBC Nikko sells for its own account will be reduced by the number of such excess, resulting in a decrease in the number of repurchased own shares subject to the Subsequent Adjustment Transaction and a lower ceiling on the number of shares issued with respect to the ASR Share Options With a Fixed Amount of Investment.

     • In this case, the ASR Share Options With a Fixed Number of Shares will not be exercised and will be waived by SMBC Nikko.

  2. When the Average VWAP is lower than the per-share purchase price in the Share Repurchase (ASR) (Subsequent Adjustment Transaction via exercise of the ASR Share Options With a Fixed Number of Shares)

     • In this case, assuming that SMBC Nikko purchases shares at the Average VWAP in the Market Purchase Transactions (ASR), SMBC Nikko will be able to purchase the number of shares required to return the borrowed shares without using all the amount it received from the Company in the Share Repurchase (ASR) (Received Amount (Nikko)) (the amount of money required to purchase such number of shares as is necessary to return the shares borrowed by SMBC Nikko under such assumption is hereinafter referred to as the “Required Amount for Purchase (Average VWAP)”). As such, SMBC Nikko will exercise the ASR Share Options With a Fixed Number of Shares on the trading day following the last day of the Market Purchase Period (ASR), and pay to the Company an amount equivalent to the surplus as consideration for the exercise. The number of shares to be issued upon exercise of the ASR Share Options With a Fixed Number of Shares shall be 100 shares, and the amount of money delivered to the Company as a result of such exercise (exercise price) shall be calculated by the following formula:

       Exercise price of the ASR Share Options With a Fixed Number of Shares

       = Received Amount (Nikko) – Required Amount for Purchase (Average VWAP)

       (Required Amount for Purchase (Average VWAP) = Number of Shares Sold (Nikko) x Average VWAP)

       * The exercise price described above represents the amount to be paid for the issuance of 100 common shares of the Company.

     • The actual total purchase price of own shares that the Company will repurchase in the Scheme as a result of payment of the exercise price for the exercise of the ASR Share Options With a Fixed Number of Shares above will be the total purchase price that the Company paid in the ToSTNeT-3 transactions less the exercise price of the ASR Share Options With a Fixed Number of Shares.

     • Assuming that the aggregate amount of sell orders from the general shareholders and the Anticipated Number of Shares Repurchased (ASR) does not exceed the Maximum Number of Shares Repurchased in the Share

       Repurchase (ASR) (all the Anticipated Number of Shares Repurchased (ASR) are sold by the SMBC Nikko for its own account), the result will, by combining the Share Repurchase (ASR) and such Subsequent Adjustment Transaction, be the same as the case where the Company purchases 2,250,000 shares, which is the Anticipated Number of Shares Repurchased (ASR), at the Average VWAP (this does not take into account the 100 shares to be delivered at the time of exercise of the ASR Share Options With a Fixed Number of Shares). If the aggregate amount of sell orders from the general shareholders and the Anticipated Number of Shares Repurchased (ASR) exceeds the Maximum Number of Shares Repurchased, the number of the Company’s shares that SMBC Nikko sells for its own account will be reduced by the number of such excess, resulting in a decrease in the number of repurchased own shares subject to the Subsequent Adjustment Transaction and a lower ceiling on the exercise price of the ASR Share Options With a Fixed Number of Shares.

     • In this case, the ASR Share Options With a Fixed Amount of Investment will not be exercised and will be waived by SMBC Nikko.

• In case, for example, the tender offer for the Company’s common shares is commenced or announced, the exercise price of, and the number of issued shares for, the ASR Share Options With a Fixed Amount of Investment or the ASR Share Options With a Fixed Number of Shares will be adjusted, in order to make any adjustments for the unexecuted portion of the Market Purchase Transactions (ASR) intended to return the borrowed shares, taking into consideration the number of trading days from the commencement or announcement of such tender offer to the last day of the Exercise Period (as defined below), after conducting subsequent adjustment transactions based on the average VWAP during a certain period up to the commencement or announcement of such tender offer, in accordance with the Terms and Conditions of Issuance of the Share Options (the exercise of either of the Share Options for which the exercise price of, and the number of issued shares for, the Share Options will be adjusted, for example, upon the commencement or announcement of the tender offer for the Company’s common shares, is hereinafter referred to as the “Exercise of Share Options upon Tender Offer”).

The exercise of either of the ASR Share Options With a Fixed Amount of Investment or the ASR Share Options With a Fixed Number of Shares will be, in principle, conducted during the period from September 15, 2026 to February 1, 2027 (the “Exercise Period”), as set forth in the Allotment Agreement. However, if SMBC Nikko notifies the Company of the occurrence of market disruption date that requires an extension of the Exercise Period of the Share Options, the Exercise Period may be extended by a number of trading dates equal to the required number of days, up to a maximum of February 12, 2027, which is the last day of the exercisable period specified in the Terms and Conditions of Issuance of the Share Options (the “Exercisable Period”), and the Share Options may be exercised on or after the first day of the Exercisable Period, regardless of the Exercise Period, in the case of the Exercise of Share Options upon Tender Offer. The final results of the Subsequent Adjustment Transaction will be separately released, but the final total purchase price or the final number of shares repurchased may vary depending on such results.

If the Average VWAP equals the per-share purchase price in the Share Repurchase (ToSTNeT-3), SMBC Nikko shall waive both the ASR Share Options With a Fixed Amount of Investment and the ASR Share Options With a Fixed Number of Shares.

(Note): In the “Initial” transactions, the Share Repurchase (ToSTNeT-3), other than the purchase from SMBC Nikko (Share Repurchase (ASR)), and the Share Repurchase (Market Purchases) are also planned to be conducted, but are omitted from the above figure.

＜Reference Information: Subsequent Adjustment Transaction＞

(Note) 1. This is a numerical example that assumes that the aggregate amount of the sell orders from general shareholders and the Anticipated Number of Shares to be Repurchased (ASR) does not exceed the Maximum Number of Shares to be Repurchased (all the Anticipated Number of Shares Repurchased (ASR) are sold by the SMBC Nikko for its own account). This does not take into account the amount of contribution at the time of exercise of the ASR Share Options With a Fixed Amount of Investment (1 yen), and the number of issued shares at the time of exercise of the ASR Share Options With a Fixed Number of Shares (100 shares).

(Note) 2. The “Substantial number of share repurchased” and the “Substantial total amount of share repurchased (JPY million)” are the number of shares or the amount in the Share Repurchase (ToSTNeT-3) as a whole, including the Share Repurchase (ASR) from SMBC Nikko. For the Share Repurchase (ToSTNeT-3), it is assumed that the aggregate amount of the sell orders from general shareholders and the Anticipated Number of Shares to be Repurchased (ASR) will equal the Maximum Number of Shares to be Repurchased.

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