By Svea Herbst-Bayliss

Feb 17 (Reuters) - Electronic trading firm CitadelSecurities last month played a critical role in processingretail investors' orders and was not involved in online tradingapp Robinhood's decision to limit trading in GameStop, Citadel'sfounder Kenneth Griffin said.

Griffin, who has been trading stocks for more than half hislife, also laid out his ideas for improving trading for all,suggesting shorter settlement cycles and transparent capitalmodels could be introduced now.

The 52-year old billionaire investor, who founded hedge fundCitadel LLC in 1990 and co-founded Citadel Securities in 2002,will deliver prepared remarks and answer questions for the U.S.House of Representatives' Committee on Financial Services onThursday, giving his most detailed public description yet ofevents that unnerved markets for days in January.

"When others were unable or unwilling to handle the heavyvolumes, Citadel Securities stepped up," Griffin said,describing the frenzied retail stock trading when CitadelSecurities processed 7.4 billion shares for retail investors onJan. 27. "That day Citadel Securities executed more shares forretail investors than the average daily volume of the entireU.S. equities market in 2019," he said.

Citadel Securities, led by Peng Zhao, competes with othermarket makers for order flow from companies like Robinhood andreceives a large percentage of orders based on executionquality. It also pays Robinhood to process orders it receives.

Retail investors have benefited from technology thatcompanies like Citadel Securities are employing to speed tradingand help cut fees, Griffin said. But last month's events -- whenan army of retail investors sent up the stock prices of unlovedcompanies like GameStop -- illustrate that more work is needed.

Trades should be settled faster, Griffin said noting thatthe trade date now usually takes two business days to settle.

"Individual investors are better served by America’s marketsthan ever before, and it is critical that our markets continueto be a force for fairness and integrity worthy of investorconfidence and participation," Griffin said.(Reporting by Svea Herbst-Bayliss; Editing by David Gregorio)