69% เป็นการส่งไปที่ราคาเสนอขายหรือเสนอซื้อที่ดีที่สุด ช่วย ลดต้นทุนในการซื้อขายจาก bid-ask spread ท่ีแคบลงของตลาดโดยรวม 5 79% of AT order were liquidity making While 75% of normal trading were

included in our study - Bid Ask spread included in the transaction costs ◦ The study results indicate a potential of market efficiency .

Put Call Future Parityโดยใช้ SET50 Index Futures เป็นสินค้าอ้างอิงในศึกษาครัง้นีโ้ดยพิจราณาข้อมูลตัวท่ีมี คุณสมบัติวันหมดอายุภายใน 1 เดือนและมีราคาเสนอซือ้ เสนอขาย(Bid Ask)ของทัง้ SET50 Index Futures

T=0 T=1 Bid Quantity Price Ask Quantity Bid Quantity Price Ask Quantity 3,000 ATO 40,500 3,000 ATO 40,500 8,800 179.50 91,400 8,800 179.5 91,400 177.00 54,000 177.0 54,000 60,100 176.50 36,500 60,100

(1) the changing IT usage in business practices, (2) the increasingly sophisticated technical approaches and mechanisms of cyber threats, (3) the revisions to preventive measures for addressing

on their behalf by those agents. As sophisticated investors with influence, often including voting rights, institutional https://www.sec.or.th/cgthailand/TH/Documents/Assessment/ICGN%20Institutional

(all IPs) and unique Ips. • This increase is especially so for low-visibility firms as compared to high-visibility firms (as proxied by the bid-ask spread). Interpretation • When the firm has news to be

140 2002 2003 2004 2005 2006 $ b n 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 % SET Turnover Share of Asia (ex Jp) 12 2.1.3 *#(#" (transaction cost) SET *#(#"P ,")'N ! Bid-Ask Spread (indirect cost) bK$! R

. (1996), Bacidore (1997), Bessembinder (2000), Goldstein and Kavajecz (2000), and Chung et al. (2004)). • The first prediction is by Harris (1994) who expects that bid- ask spreads should narrow following

their interests and on their behalf by those agents. As sophisticated investors with influence, often including voting rights, institutional https://www.sec.or.th/cgthailand/TH/Documents/Assessment/ICGN