Which statement accurately describes the closing phase difference between CLOB and MMB?

Which statement accurately describes the closing phase difference between CLOB and MMB?

• A. CLOB closing may include a closing auction; MMB closing is without a closing auction
• B. Both always include a closing auction
• C. Neither uses closing auctions
• D. Both use closing auctions in all cases

Answer: (A)

In the closing phase, price discovery is often handled differently by different market structures. A Central Limit Order Book typically uses a closing auction as part of its end-of-day process, where orders are aggregated and matched at a single closing price to maximize executed volume and create an orderly close. This auction helps establish a fair final price by bringing together supply and demand in one final sweep. The MMB, in contrast, does not employ a closing auction in its closing phase. Its end-of-day activity follows the market’s normal trading mechanics, and there isn’t a dedicated closing auction to set the final price. So the closing phase difference is that the closing may include a closing auction for a CLOB, while the MMB closes without one. That’s why this option is best: it captures the potential for a closing auction in a CLOB and the absence of such an auction in the MMB. The other statements mischaracterize the realities—either claiming closing auctions happen in all cases or in none at all.

In the closing phase, price discovery is often handled differently by different market structures. A Central Limit Order Book typically uses a closing auction as part of its end-of-day process, where orders are aggregated and matched at a single closing price to maximize executed volume and create an orderly close. This auction helps establish a fair final price by bringing together supply and demand in one final sweep.

The MMB, in contrast, does not employ a closing auction in its closing phase. Its end-of-day activity follows the market’s normal trading mechanics, and there isn’t a dedicated closing auction to set the final price. So the closing phase difference is that the closing may include a closing auction for a CLOB, while the MMB closes without one.

That’s why this option is best: it captures the potential for a closing auction in a CLOB and the absence of such an auction in the MMB. The other statements mischaracterize the realities—either claiming closing auctions happen in all cases or in none at all.