PT  - JOURNAL ARTICLE
AU  - Giovanni Petrella
TI  - Protecting Market Makers from Scalpers in Option Markets
DP  - 2008 Sep 21
TA  - Trading
PG  - 65--71
VI  - 2008
IP  - 1
4099  - http://guides.pm-research.com/content/2008/1/65.short
4100  - http://guides.pm-research.com/content/2008/1/65.full
AB  - Scalpers are traders who establish and liquidate an option position quickly, even for very small gains in relative terms. Scalpers trade very frequently during the day to make intraday profits without holding any hedge position in the underlying market and without carrying inventory overnight. This article shows that: option market makers bear losses when trading with successful scalpers; scalpers may design successful trading strategies exploiting some evidence of intraday short-run return predictability; option market makers may protect from scalping risk by quoting a bid-ask spread that makes after transaction costs profits for scalpers equal to zero; and option market makers in the Italian and Australian covered warrants markets do actually quote a bid-ask spread that protect them from scalpers.