The spread is a per-name fact

Commodities taught that one instrument carries many spreads - by month. Equities compresses that lesson into the day: one name, one book, and a spread that breathes with the clock and gasps with the news.

The daily shape

Spreads are widest at the open - the auction has batch-priced the overnight, and the continuous book starts sparse - then tighten through the morning to their calm-hours normal, and stay tight into the close's depth. The pattern is the commodities liquidity clock wearing equity clothes, and it prices the same discipline: the same order costs measurably more in the first minutes than an hour later, in any name, every day.

The per-name profile

• Tier sets the base: module 1's hundredfold range means a 'normal' spread is a per-name fact to be learned, not assumed.
• News stretches it: spreads widen into scheduled earnings and snap wide on unscheduled announcements - makers step back from the coin toss exactly as commodity makers do before a report.
• Stress compounds it: the small-cap exit that cost 1% in calm costs several in panic - the module 1 warning, now as a number to budget rather than a caution to note.

Reading it, practically

Watch a name's touch for a week before trading it seriously: its calm normal, its open behaviour, its reaction to its sector's news. That profile is the execution half of module 3's cost arithmetic, and it converts the spread from a surprise into a scheduled expense. The reading habit transfers from every prior track; only the axis changed - months there, names and hours here.