Composite calculation

[stenzrob]

I noticed on my streamer today that the nasdaq composite jumped up and down instantaneously several times. This is also seen in the intraday chart at marketwatch. And yet, the nasdaq 100 index does not make similar jumps. Is nasdaq perhaps having a problem with ther computers? I recall that the instantaneous drop in dow on "china syndrome" day was attributed to backlog of orders clearing their computers.

[IIC]

I was on a chat at the time when the Nasdaq jumped over 7 points on a tick and the Nas 100 went down...Knew it had to be a mistake with about a minute left...I see the Nasdaq corrected the close now.

Funny tho...2 people said they had stocks that gapped way down at the exact same time...Can't remember the tix tho but they were Nas but not on the Nas 100...Doug

[IIC]

Associated Press
Erroneous Trades Cause Nasdaq Surge
Associated Press 03.23.07, 4:35 PM ET

The Nasdaq composite index jumped more than 7 points in afternoon trading Friday after a glitch caused one of its components to surge more than 11,000 percent.

Several trades were processed just before 2 p.m. EST that valued insurer Donegal Group (nasdaq: DGICA - news - people ) Inc. shares at about $1,999 - well above the $18 level it was trading at earlier in the session.

Bethany Sherman, a spokeswoman for Nasdaq Stock Market (nasdaq: NDAQ - news - people ) Inc., said the exchange immediately canceled those trades and the index was adjusted. She said it had not yet been determined how the erroneous trades were processed.

"This was a brief incident," she said. "The trades were canceled, but it did cause the index to go up 7 points."

Shares of Donegal rose 33 cents, or nearly 2 percent, to close at $18.

[stenzrob]

Associated Press
Erroneous Trades Cause Nasdaq Surge
Associated Press 03.23.07, 4:35 PM ET

The Nasdaq composite index jumped more than 7 points in afternoon trading Friday after a glitch caused one of its components to surge more than 11,000 percent.

Several trades were processed just before 2 p.m. EST that valued insurer Donegal Group (nasdaq: DGICA - news - people ) Inc. shares at about $1,999 - well above the $18 level it was trading at earlier in the session.

Bethany Sherman, a spokeswoman for Nasdaq Stock Market (nasdaq: NDAQ - news - people ) Inc., said the exchange immediately canceled those trades and the index was adjusted. She said it had not yet been determined how the erroneous trades were processed.

"This was a brief incident," she said. "The trades were canceled, but it did cause the index to go up 7 points."

Shares of Donegal rose 33 cents, or nearly 2 percent, to close at $18.

Interesting. Thanks for the follow-up Doug.

Lesson here: use limit orders