Glitch disrupts online trading for some TD Ameritrade clients

* Many stock quotes not recognized on main online platform between 12-12:30 pm

* Company says problem is resolved, but still investigating cause

By John McCrank

NEW YORK, Oct 12 (Reuters) - Electronic trading on the main online platform of TD Ameritrade , the No. 1 U.S. discount brokerage by trading volume, was disrupted for about a half hour on Friday due to a technical glitch that prevented some stock symbols from being recognized, the company said.

Between around noon and 12:30 p.m. Eastern time, clients of the Omaha, Nebraska-based brokerage were unable to get stock quotes for more than half of the most actively traded symbols on the online platform aimed at fundamental, long-term investors, said Steve Quirk, head of the firm's Trader Group unit.

"We had an issue with a subset of our quotes, and as a result of that, when clients would pull up a quote, the price, or any of the other fundamental data that would usually populate, was not populating," he said.

Affected clients could see all of their positions at all times and could phone TD Ameritrade to place any trades, he added.

The company, which had over 5.7 million funded accounts as of June 30, said the cause of the problem was still being investigated.

TD Ameritrade's online and mobile platforms aimed at more advanced traders -- Trade Architect and thinkorswim -- were not affected, said spokeswoman Kim Hillyer.

"The issue has been resolved and we apologize for the inconvenience to our clients," she said.

(Reporting by John McCrank; Editing by Leslie Adler)

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