Voice trading, speech recognition and call recording rules

Latest

Accents, crosstalk and the phone line: where speech recognition slips

A Stanford-led study of five commercial recognizers, published in 2020, measured an average word error rate of 0.35 for Black speakers and 0.19 for white ones. On a trading desk, narrowband phone lines, crosstalk and clipped jargon push the error count higher again.

Oct 30, 2026 4 min read

On the line

Screens took over most of the dealing room, but the room never went quiet. Large bond trades, currency blocks, energy contracts and many derivatives are still agreed in a conversation between a broker and a client, and every figure spoken on that line can end up as a price. Floor Noise is an independent publication about the spoken side of the markets: how voice trading still works, how software learns to transcribe it, and the rules that oblige firms to keep what was said.

Speech technology is about the machines. A general speech recognizer learns from dictation, audiobooks and meetings, so it stumbles when a dealer asks for a yard, reads out a ticker at speed or speaks over a noisy desk line. The section explains how these systems are measured, beginning with word error rate, and why accents, crosstalk and narrowband audio push the errors up.

Voice in the markets covers the desks. It describes how voice trading desks still work, with their turret phones, private wires and squawk boxes, and what happened once transcripts reached the surveillance teams. It also follows the retail end, where a recorded call can protect a small investor as much as a bank.

Records and rules is the recordkeeping shelf. Investment firms in the European Union have been required since January 2018 to record calls and messages that lead, or are meant to lead, to a trade, while in the United States the duty is divided between the futures and securities regulators. Pages here compare the European and American recording rules and set out how long trade recordings must be kept.

Each page carries a date, and the rules or figures in it hold as of that date. No page sells a product, recommends a vendor or asks for a demo request. The archive lists everything in date order, and the about page says what the site is and what it is not.

Line by line

Speech technology

Software that turns a dealer's words into text, and the ways it goes wrong.

Word error rate, and what it leaves out

Word error rate, usually shortened to WER, is the number most often quoted for a speech recognizer. Computing it takes three steps. Line up the machine’s transcript against a reference transcript typed by a person. Count the words the machine got wrong, the words it missed and the words it added. Divide that total by the number of words in the reference.

May 9, 2017 4 min read

Speech-to-text built for the trading floor

A bond salesperson who says “I’ll pay fifteen for a yard” has made an exact statement. The price is fifteen after leading digits both sides already know, and a yard is a billion. A general speech recognizer hears the same sounds and tends to write something about gardening. That distance between what a trading floor says and what a consumer engine expects to hear is why speech-to-text for the markets has become a specialty of its own.

Voice in the markets

The conversations that still move prices, and the people on each end.

How voice trading desks still work

Walk onto a sales and trading floor at a large bank and the screens are the first thing anyone notices: four, six, sometimes eight to a seat. The second is the phone, a console with dozens of buttons, two handsets, a row of speakers and a microphone on a stalk. That console is called a turret, and for all the growth of electronic trading it remains the working tool of anyone whose job involves agreeing a trade by voice.

Oct 30, 2026 3 min read

What transcription changed for trade surveillance

Chat logs carried the evidence when the CFTC fined five banks $1.4 billion in 2014 over foreign exchange benchmarks. Most recorded calls went unheard, because listening to a trader’s day of calls takes a day. Machine transcription turned that audio into text, which now runs through the same phrase lexicons and alerts that chat and email already faced.

Oct 30, 2026 5 min read

Voice on the record, and never borrow to win it back

Since January 2018 a European broker has had to tape every call meant to lead to a client order, and in Spain a client buying a complex product by phone must say a warning aloud for that tape. The CNMV’s 2023 ban on funding CFD accounts with a credit card follows the same logic, and it applies as much to a quick loan from Avinto taken to win back a loss.

Records and rules

What regulators require firms to tape, and for how long.

How long trade recordings must be kept

A recorded trading call in the EU must be kept five years under MiFID II, or seven if the regulator asks. In the United States a futures firm’s audio falls under CFTC Regulation 1.31, which sets one year, while the chat about the same trade stays for five. SEC and FINRA rules sit at three years.

Oct 30, 2026 4 min read

Trade call recording rules: MiFID II, the CFTC and FINRA

A trader’s call to a client about a bond is recorded almost everywhere, but the legal reason for the recording differs by jurisdiction and by product. In the European Union the obligation is broad and set for every investment firm. In the United States it depends on whether the trade is in futures and swaps or in securities, and in securities the direct taping duty is narrow.