If a purchaser has a rebate sharing contract, a pharmacy benefits manager shall offer to provide the purchaser a report for each fiscal quarter and each fiscal year that contains the amount of the: net revenue of the pharmacy benefits manager from sales of prescription drugs to purchasers made through the pharmacy benefits manager’s network of contractually affiliated retail pharmacies or through the pharmacy benefits manager’s mail order pharmacies, with respect to the pharmacy benefits manager’s entire client base of purchasers; total prescription drug expenditures applicable to the purchaser; total manufacturer payments earned by the pharmacy benefits manager during the applicable reporting period; and total rebates applicable to the purchaser during the applicable reporting period. If the exact amount of each item to be reported under subsection (a) of this section is not known by the pharmacy benefits manager at the time of its report, the pharmacy benefits manager shall offer to provide: its current best estimate of the amount of each item; and an updated report containing the exact amount of each item immediately after it becomes available. A pharmacy benefits manager shall provide the information described in subsections (a) and (b) of this section if requested by the purchaser. Notwithstanding the provisions of paragraph (1) of this subsection, if a pharmacy benefits manager requires a nondisclosure agreement under which a purchaser agrees that the information in subsections (a) and (b) of this section is proprietary information, the pharmacy benefits manager may not be required to provide the information until the purchaser has signed the nondisclosure agreement.