The telegraph killed a profession that nobody remembers
Before 1844, a fast horse could make you rich by bringing London prices to Liverpool a day before anyone else. After the telegraph, that trade was gone in an afternoon.
For most of commercial history, the single most valuable commodity in finance was a piece of paper moving faster than another piece of paper. A merchant in Liverpool with yesterday's London cotton prices could buy from a merchant in Liverpool who did not yet have them. The difference was pure profit. Couriers on horseback, carrier pigeons, clipper ships, semaphore towers, all existed to close that gap. The Medici banking network had run on the same logic three centuries earlier. Entire careers were built on being faster than the person next to you.
The electric telegraph ended most of that in about twenty years.
The timeline
Samuel Morse sent the first meaningful US telegraph message in May 1844 between Washington and Baltimore. William Cooke and Charles Wheatstone had been operating a working system on British railways since 1837. Paul Julius Reuter set up a carrier-pigeon news service between Aachen and Brussels in 1850 and replaced it with a telegraph line the next year. His company, Reuters, still exists.
The transatlantic cable, after several failed attempts, went into permanent operation in 1866. For the first time, a trader in New York could know the London cotton price within hours rather than weeks. Arbitrage between the two markets, which had been an enormous source of trading profits, collapsed almost immediately.
What replaced it
When the old information edge disappeared, a new one took its place. If everyone has the same prices, the edge moves to whoever can interpret them fastest, hold the biggest position, or time the news against the next data point. That edge has been compressing ever since. Bloomberg terminals (1981), algorithmic trading (1980s onward), and microsecond-level co-location (2000s onward) are all descendants of the same logic.
The 1866 transatlantic cable compressed a week of information lag into a few hours. In April 2025, an algorithm acted on a Truth Social post 13 seconds before the rest of the world noticed. The gap between signal and reaction has been closing for nearly two centuries, and every era has had the same structural lesson. Whoever is closest to the source wins. See it happening live.
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