Under the terms of the 2003 agreement in which IDIX became a majority-owned subsidiary of IDIX, NVS has the contractual right to maintain its equity stake in IDIX by buying shares to offset new shares arising from exercises of stock options by IDIX’s employees. NVS has the right to buy these shares on the same terms as the IDIX employees who exercised (hence the 4.05/sh purchase price in the Form-4 filing above).
NVS’ equity stake in IDIX remains 55.6% (see next post).