Why Nasdaq and NYSE have different opening prices?

Discussion in 'Order Execution' started by sloth, Mar 12, 2009.

  1. sloth


    I regularly use "limit on open" sell orders through TDAmeritrade.

    Today I had 3 orders executed worse than the opening prices according to NYSE/Yahoo.

    NM: NYSE open 2.4, Nasdaq open 2.34
    KNL: NYSE open 5.75, Nasdaq open 5.72
    OB: NYSE open 8.67, Nasdaq open 8.42

    On the other hand, the open prices on Nasdaq and NYSE usually agree, so I am confused, when and why they have different open prices?

    TDA told me that Nasdaq has "opening cross" mechanism where all orders entered by 8:58am participate the opening, is there a similar mechanism through NYSE?

    Thanks in advance!
  2. Yes, the NYSE has an auction. So limit on open (OPG) get into the auction and you get the NYSE specialist open price if it's in your limit.
    Also, on Yahoo the opening price is shit. It's consolidated data from all ECN's so the open price could be on 100 shares 1 dollar off the fair value.
    The beauties of trading the open.