Europe's STOXX 600 opening delayed due to data input problems

LONDON (Reuters) - Europe's key STOXX <.STOXX> <.STOXX50> indexes opened more than an hour late on Monday after an outage due to "input data problems", the index operator Qontigo told its clients.

The delay comes at the start of a crucial week for markets as traders prepare for market volatility ahead of the U.S. elections on Tuesday.

The issue did not affect trading of single stocks, although it likely impacted derivatives or exchange traded funds whose prices are based on the pan-European STOXX 600 levels.

"Our input data and index calculation have been affected by input data problems," said, Qontigo, which is owned by Deutsche Boerse <DB1Gn.DE>. Qontigo's spokesman did not give further details on the reason for STOXX's failure this morning.

The STOXX 600 index opened an hour and six minutes late and was trading 0.4% higher at 343.6 points as of 0915 GMT.

The outage follows Euronext's widespread disruption last month affecting trading from Dublin and Amsterdam to Paris and Lisbon.

There have been a string of breakdowns this year on international exchanges, including a hardware failure at the Tokyo Stock Exchange, cyber attacks that hit New Zealand's stock exchange, and a software glitch at Germany's electronic trading platform Xetra, also managed by Deutsche Boerse.

(Reporting by Thyagaraju Adinarayan; Editing by Rachel Armstrong and Giles Elgood, Kirsten Donovan)