News | The Investor
25 Jan 2026 2:36
NZCity News
NZCity CalculatorReturn to NZCity

  • Start Page
  • Personalise
  • Sport
  • Weather
  • Finance
  • Shopping
  • Jobs
  • Horoscopes
  • Lotto Results
  • Photo Gallery
  • Site Gallery
  • TVNow
  • Dating
  • SearchNZ
  • NZSearch
  • Crime.co.nz
  • RugbyLeague
  • Make Home
  • About NZCity
  • Contact NZCity
  • Your Privacy
  • Advertising
  • Login
  • Join for Free

  •   Home > News > Business > Features > The Investor

    Beware Fat Fingers and Black Boxes

    Was a 'fat finger' to blame for Wall Street’s recent implosion? The US Securities & Exchange Commission has launched an investigation after the main measurement of the US market, the Dow Jones Industrial Average, fell by 1000 points a few weeks ago. This was the biggest points drop since 1987.


    Investment Research Group
    Investment Research Group
    Some shares were particularly badly hit. Consulting and outsourcing giant Accenture fell from US$42.30 to just 4USc, water sector investment fund PowerHouse dropped from US$18 to 10USc and even conservative household goods producer Procter & Gamble slumped from over US$60 to around US$37.

    Once it was found there was no market panic, those shares recovered much of their losses by the end of the day.

    The index rebounded the next day after it was announced that "erroneous" trades had caused the slump. In other words, somebody, somewhere had made a mistake.

    One theory is that a trader tried to sell a million dollars worth of a share or shares and instead put in an order for a billion dollars – the so-called ‘fat finger’ problem where the wrong key or keys are hit on a keyboard.

    Another contributing factor is likely to have been the ‘black box’ trading systems that act in microseconds and have no human input. These would have seen someone placing big sell orders and followed suit.

    As US market analyst Sol Palha notes, at one stage the US index lost 600 points in just seven minutes.

    "Humans could never move that fast. There are rumours that a trader entered billion instead of million and this triggered the massive sell off. Whatever the cause, the main wave of selling was initiated by computers."

    Such computers use quantitative programs that determine which investment strategy is going to yield a superior rate of return.

    "It is assumed that because computers have no emotions, they should be better at trading as they can move in and out of the markets extremely rapidly. The scary part is that the computer renders the final decision.

    "There is one problem, these computers are programmed by humans and one glitch in the program can cause havoc."

    This is a big deal since, by some counts, computers are responsible for as much as 70% of daily trading volume on the New York Stock Exchange.

    As far as I am aware, NZ and possibly even Australia are too small, and the computer
    systems too expensive, to justify having black boxes to trade shares.

    However, that won’t stop our markets collapsing if the same happens in the USA and we have to hope that action is taken to ensure it does not happen again.

    © 2026 David McEwen, NZCity

     Other The Investor News
     12 Sep: Fixed vs. floating rates – which is best for you?
     Top Stories

    RUGBY RUGBY
    Olympian Sam Tanner has records in his sights ahead of this evening's mile race at Cooks Gardens in Whanganui More...


    BUSINESS BUSINESS
    US copied Iran's Shahed drones — now they are deployed in the Middle East More...



     Today's News

    Environment:
    MetService has issued watches for rain and wind 21:56

    Law and Order:
    An 18 year-old has been arrested and charged in relation to a spate of burglaries last night in Cambridge 21:16

    Tennis:
    Despite battling cramp on a sweltering day seven of the Australian tennis Open, reigning back-to-back men's champion Jannik Sinner is in the box seat to progress to the fourth round 18:56

    Politics:
    Two women believed to have been killed in the Mount Maunganui campground landslide were friends 18:36

    International:
    US looks to South Korea to take 'primary responsibility' in monitoring Kim Jong Un and North Korea 18:16

    Law and Order:
    Pakuranga College is paying tribute to two of its students caught in the Mount Maunganui landslide 18:06

    Rugby:
    Olympian Sam Tanner has records in his sights ahead of this evening's mile race at Cooks Gardens in Whanganui 17:46

    Law and Order:
    Police have released the full list pf names of the six people unaccounted for following the landslide at the Mount Maunganui Campground on Thursday 17:26

    Lower South Island:
    Southland rider Josh Burnett has banked his third career win in cycling's Tour of Southland, finishing safely in the peloton to take the overall title by 10 seconds from Cambridge's Matthew Wilson 17:06

    International:
    Human remains found as New Zealand landslide search moves to recovery 16:56


     News Search






    Power Search


    © 2026 New Zealand City Ltd