[guga42k]

What you describe is directional trade (aims to capture up/down moves in underlying).

Investment banks usually trade in volatility space, also called delta hedged. Main idea they would sell options (calls or puts) by adding extra premium to the fair price. At the same time they make the whole portfolio delta neutral by buying and selling underlying instruments on daily basis. By having significant portfolio one could expect to leak less on the hedging process and may be use some correlation between underlyings and use index futures instead of individual stocks. The whole business is to capture the premium mentioned above without predicting up or down move.