SAN FRANCISCO (Dow Jones)--The Nasdaq Stock Market said Google Inc. (GOOG) shares' Tuesday closing price will be adjusted to $400.52 after possibly "erroneous trades" at the end of Tuesday's session sent share prices down more than 16% in two minutes.

Meanwhile, Nasdaq also canceled trades of Google shares above $425.29 or below $400.52 executed during the last three minutes of Tuesday's session.

A spokeswoman said the exchange continues to investigate the cause. A glitch is suspected.

"Participants should review their trading activity for potentially erroneous trades and request adjudication," Nasdaq said in a statement.

A Google spokesman didn't have an immediate comment.

Before the trades were investigated, Google shares had ended the day down 16% to $320.52, according to FactSet Research, a nearly two-year low. They then fell more than 16% at the tail-end of the session. Shares recently rebounded sharply after-hours to trade at $413.06.

Google shares have been under pressure in recent weeks because of concerns about the online advertising market's stability as the global economy weakens. But on Tuesday, there doesn't seem to be a fundamental reason for such a dramatic drop.

Meanwhile, according to FactSet, there were at least seven trades of Google shares for one penny a share in the last two minutes.

Nasdaq also is investigating certain Tuesday trades of Philadephia-based Rohm & Haas Company (ROH), a provider of specialized technologies for a variety of industries. It canceled trades of Rohm & Haas shares above $73.20 and below $68.93 during the session's last three minutes.

-By Ben Charny, Dow Jones Newswires; 415-765-8230; ben.charny@dowjones.com

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