Intraday sector pairs hedged as one spread

Two sector names, one gap

The archive describes a pairs-trading case that used two highly capitalized pharmaceutical names in the same sector, MRK and LLY, because their historical prices tracked each other and had crossed the same level more than once.

The starter pairs-trading construction sold the richer name and bought the cheaper name, then planned to close both legs when the two prices met. Both legs were marked as one spread-ticket, not as two separate stock opinions.

No leanable-book, no first leg

A first leg was initiated only if a bid or offer in the other name could be leaned on. That live second-name bid or offer is the leanable-book. If it was not present, the pairs-trading setup was left untouched.

The hedging-strategy is the completion rule for the second leg. If the first name did not move as expected in a short window, that hedge was hit: the second name was sold on the bid so the book became a sold pair marked as one differential, illustrated at 5.00, instead of an unhedged single name.

That marked spread could then be scaled near 5.50 or covered near 4.50. Adds and exits were decided from the differential, not from either name's story.

Channel edges as one instrument

A pair that stayed inside a 4.00 to 6.00 channel was handled like support and resistance on a single instrument. That is the commodity-spread-trading habit of working the differential at the channel edges, so fade or scale decisions stay one signal rather than two outright views.

AOL versus VIA as a sold spread

One watched pair, AOL versus VIA, had a printed gap between 3.50 and 6.80. As that gap approached 6.00 while the broader tape weakened, the harder-to-borrow name, the hard-side, was sold short and later covered at a lower price, more than once.

When that short could not be bought back and the gap widened, the other name was bought so the position remained a sold spread near 6.00.

The recounted case scaled to three 2000-share spread units with sells near 5.80, 6.31, and 6.88, then bought the 6.88 unit near 6.25 and the remaining two near 5.00 after the gap began to narrow.

A full-session order-envelope

Working the book required a full-session order-envelope of buy and sell orders so entry, add, cover, and abstention stayed one procedure.