Quantity allocation for periodic call auction when opening price is formed in the upper or lower limit price

In case of periodic call auction, trading is concluded according to the principle of priority in price·time, but as far as opening price is formed in the upper or lower limit price, allocation of concluded quantities shall be made in sequence from the largest quantities of an offer price to the smallest ones on the basis of principle of priority in quantity as shown in the following order while allocation of other cases shall be in the principle of time priority.

  • 100 times of trading quantity unit
  • 500 times of trading quantity unit
  • 1,000 times of trading quantity unit
  • 2,000 times of trading quantity unit
  • a half of balance (quantity below the said unit shall be rounded off to the nearest integer)
  • remainder

If opening price is determined as KRW20,150 (the upper price limit), for instance, quantities at selling offer price shall be allocated according to the order of priority in quantity between buying offers at the upper price limit.

status of offer price
status of offer price
Selling order(Q'ty) price Buying order(Q'ty)
4,000 1,500 600 (6,100) 20,150 (16,200)
1,000

200

10,000

5,000
1,700 1,500 (3,200) 20,100 500 700
1,300 1,000 (2,300) 20,050 400
800 (800) 20,000
700 (700) 19,950
13,100 total 16,200
No. ①, ② & etc mean the sequences of receiving offer price
outcome of trading
outcome of trading
category No.③ offer price
(10,000 shares)
No.④ offer price
(5,000 shares)
No.① offer price
(1,000 shares)
No.② offer price
(200 shares)
① 100 times of trading unit 100 100 100 100
②500 times of trading unit 500 500 500 100
① 1,000 times of trading quantity unit 1,000 1,000 400
① 2,000 times of trading quantity unit 2,000 2,000
① a half of balance 3,200 700
③ remainder 800
executed quantity (13,100 shares) 7,600 4,300 1,000 200
status of offer price & trading after determination of opening price
status of offer price & trading after determination of opening price
Selling order(Q'ty) price Buying order(Q'ty)
⑤ 3,000 ⑦ 1,000 ⑨ 500 20,150 ③ 2,500 ④ 700 ⑥ 1,000 ⑧ 500
With buying remainder of 3,200 shares at the upper price limit, received offer prices of No. ⑤~⑨ after determination of opening price,

After the determination of opening price, conclusion is made as per ⑤-③2,500 shares, ⑤-④500 shares, ⑦-④200 shares, ⑦-⑥800 shares, ⑨-⑥200 shares, ⑨-⑧300 shares. Allocation shall be made up to the offer price of No.④, but offer prices received after opening of the market shall be concluded according to the principle of time priority.

Priority of quantity allocation for periodic call auction in case of withdrawal & revision of offer price

If whole quantities of offer prices are withdrawn in cancellation and revision of offer prices, pertinent offer price itself is cancelled so that participation is not allowed for succeeding trading, and actual receiving time shall be considered as acceptance time of offer price for revised quantities in the case of partial revision and for non-conclusion balance at the pertinent price in the case of whole revision of quantities, after which participation is taken so that priority order of trading shall not be affected.


However, at the time of quantity allocation when opening price is formed as upper·lower limit price in the case of balance of partial withdrawal and balance of partial revision, if partial revision or partial withdrawal is made and the quantities become less under the condition that offers of withdrawal·revision are allocated earlier than offers with smaller quantities according to quantity first rule, then the quantities which deduct withdrawn·revised quantities from original quantities shall be regarded as original quantities at the time of receipt.


Priority of quantity allocation for periodic call auction in case of withdrawal & revision of offer price
Priority of quantity allocation for periodic call auction in case of withdrawal & revision of offer price
Selling price Buying
continuous periodic call periodic call continuous
⑥ 130 ① 150 upper price limit ② 1,000
③ 500
④ 300
⑤x(③) cancel 300
Priority of quantity allocation for periodic call auction in case of withdrawal & revision of offer price
1st trading (after decision of opening price) priority of buying offer ② 1,000 ③ 500 ④ 300
allocated quantity of No.① offer price 100 50 -
2nd trading (after receipt of No.⑥) quantity of No.⑤ offer price ② 1,000 ③ 200 ④ 300
allocated quantity of No.⑥ offer price - 30 100
total distribution 100 80 100

Following are how to fix priority of simultaneous offer price due to partial withdrawal and to make proper allocation.


Priority in quantity shall be applied to the allocation of quantity when upper price limit is determined as opening price for periodic call auction in above table. Accordingly, 100 shares out of 150 shares of selling offer in No. ① shall be distributed first to buying offer in No. ② having the greatest quantities and the balance 50 shares shall be distributed to buying offer No. ③ having 2nd greatest quantities.


Thereafter if 300 shares (No. ⑤ price) are cancelled among No.③ 500 shares, the offer is deemed to be made for 200 shares from the beginning of offer receipt (50 shares already distributed are still valid) and therefore, priority of offer price shall be in the order of price of 1,000 shares No. ②, 300 shares No. ④ and 200 shares No. ③.


And, if selling offer for130 shares No. ⑥ is received, 100 shares are distributed to next priority No.④ since buying offer No.② was already distributed for basic quantities of 100 shares, and remaining 30 shares are allocated to buying offer of last priority No. ③.