ABT-W and ABBV-W trading "when issued"

Abbott Spinoff AbbVie Begins Trading to Determine Value
Excerpt:

Abbott Laboratories’ (ABT) spinoff began trading on a “when issued” basis, with investors valuing the new Abbott at $47.9 billion and the new drug company AbbVie Inc. at $55.3 billion.

The when-issued trading will set stock prices and values for the two companies when they officially split on Jan 1. Abbott when-issued shares, which are trading under the ticker ABT-W (ABT-W), began trading at $29.05 and rose 4.3 percent to $30.30 at 4 p.m. New York time. AbbVie when-issued shares, trading under the ticker ABBV-W (ABBV-W), opened at $37 and fell 5.4 percent to $35.

The secondary market for the when-issued shares is in parallel with regular Abbott stock, which fell less than 1 percent to $65.33. The Dec. 31 closing values of the when-issued shares will set the opening prices for the split companies when the break-up is complete and the two different stocks begin trading on Jan. 2.

Abbott is dividing the Abbott Park, Illinois-based company because the drug unit and other operations have grown into two distinct business lines, Chief Executive Officer Miles White has said. The split will enable investors to better value the two businesses, he said when the decision was announced last year. Stock for AbbVie, the drugmaker, will trade under the ticker ABBV while Abbott will keep its current ticker, ABT.

Investopedia explains 'When Issued - WI'
Excerpt:

Securities trade on a when issued basis when they have been announced, but not yet issued. The transaction is settled only after the security has been issued. A when-issued market exists where when issued instruments are traded. When issued markets can provide an indication regarding the level of interest that a new issue will attract. When issued transactions are dependent upon the actual security being issued and the exchange or National Association of Securities Dealers ruling that the transactions will be settled.

Comment: When Issued Images from bloomberg.com ABBV-W and ABT-W. ABT screen capture from Yahoo finance: ABT. My earlier prediction about their prices wasn't even close