NEW YORK (CNNMoney) -- The chief executive of Nasdaq OMX said he was "embarrassed" after technical glitches caused Facebook's widely-anticipated IPO to be delayed Friday, according to several news reports.
Issues stemming from a number of late order cancellations slowed the start of trading in Facebook, Robert Greifeld told reporters in a press conference Sunday.
As a result, shares of Facebook (FB) didn't start trading until 11:30 a.m. on Friday.
The glitch kept some traders from knowing for more than two hours whether their orders had been honored or cancelled, the Wall Street Journal reported. Some investors questioned whether the confusion contributed to the lackluster first day performance of Facebook's shares. (Read: Facebooks' new billionaires)
Facebook's shares ended the first trading session at $38.23 a share, just slightly higher than its $38 offering price.
However, the stock set a record for trading volume, with 567 million shares changing hands by the end of the day. The previous record of 450 million shares was set by General Motors (GM, Fortune 500) in 2010.
Nasdaq did not return calls seeking comment. 
