According to Harris, precommitted traders:

a.

Other

b.

Offer liquidity to obtain better prices for trades they want to do

c.

Trade on price discrepancies between two or more markets

d.

Complete quick round-trip trades without assuming much inventory risk

e.

Buy and sell misvalued instruments

According to Harris, market makers:

a.

Trade on price discrepancies between two or more markets

b.

Other

c.

Offer liquidity to obtain better prices for trades they want to do

d.

Complete quick round-trip trades without assuming much inventory risk

e.

Buy and sell misvalued instruments