.55 per share , the same price per share at which pca holdings llc purchased common stock in the transactions . the agreement called for these options to vest ratably over a five-year period , or upon completion of an initial public offering , full vesting with contractual restrictions on transfer for a period of up to 18 months following completion of the offering . the options vested with the initial public offering in january 2000 , and the restriction period ended august , 2001