Shares of U.K. bank HSBC briefly surged 9.8 percent in morning trade on Thursday, with market watchers blaming a trading error for the move.
At approximately 11.30 a.m. London time the lender's stock spiked nearly 10 percent before quickly falling back to resume its normal trading pattern for the session.
The brief move expanded HSBC's market capitalization by around £11 billion - to £129 billion from £118 billion. An HSBC spokesperson told CNBC they believed a trading error was behind the jump.
Traders and market analysts gave immediate responses to the spike on the social networking site Twitter. Will Hedden, a trader at IG Markets said: "(There are) some very fat fingers in FTSE land today."
(Read More: Dream run in US stocks set to end: HSBC)
His colleague, market strategist Brenda Kelly, told CNBC vie email that there appeared to be no news behind the sudden climb — and that a trading error appeared to have occurred.
"The push to 688p from 630p was very short-lived so it looks like a trader error that was very quickly reversed," she said. "Fat finger is the clear explanation."
(Read More: HSBC needs '$111 billion capital injection': Analysts)
Market analyst Ishaq Siddiqi, from the broker ETX Capital, agreed.
"Yes fat finger for sure, well-known now – shares back down now after that shocking spike," he said via email. "HSBC has been pretty volatile recently but this spike got everyone on the trading floor on their feet."
A spokesperson for the London Stock Exchange told CNBC the trade had been investigated and that no trades would be cancelled as a result.
The move had triggered a circuit breaker which automatically halted trading of the stock for five minutes, the spokesperson added.
Stock exchanges around the globe have become accustomed to trading errors causing short-lived price fluctuations.
Last August, a typing error by a clerk at the Tel Aviv Stock Exchange (TASE) caused one of Israel's largest investment firms to temporarily lose nearly 100 percent of its market value, with the Tel Aviv 25 falling 2.5 percent for a five minute period.
While the Nasdaq suffered a three-hour trading halt last year, following a technical glitch.
In China, brokerage Everbright Securities faces tough sanctions after a glitch in its computer systems caused a spike of over 5 percent in domestic stock indexes.
And Goldman Sachs experienced a trading glitch last summer that resulted in a large number of erroneous single stock and ETF options trades. Also, Germany's Eurex – a trading platform for derivative contracts – halted trading briefly last year due to unspecified technical problems.
—By CNBC.com's Matt Clinch. Follow him on Twitter @mattclinch81