Valuation of Aptina

Micron has published its 10-Q form with information on Aptina sale. The report says the following on the transaction:

"On July 10, 2009, the Company sold a 65% interest in Aptina Imaging Corporation (“Aptina”), a wholly-owned subsidiary of the Company and a significant component of its Imaging segment, to Riverwood Capital (“Riverwood”) and TPG Capital (“TPG”). Under the agreement, the Company received approximately $35 million in cash and retained a 35% minority stake in Aptina after Riverwood and TPG contributed significant debt-free capital to the independent, privately-held, company. The Company also retained all cash held by Aptina and its subsidiaries. The Company will account for its remaining interest in Aptina under the equity method. The Company’s Imaging segment will continue to manufacture products for Aptina under a wafer supply agreement and will provide services to Aptina. In the third quarter of 2009, the Company recorded a charge of $53 million, the estimated loss on the transaction, to write down certain Aptina intangible assets and property, plant and equipment to estimated fair values."

So, after the transaction Micron retains 35% of Aptina and got in exchange $35M. Assuming Aptina employees stock options are about 15%, Riverwood and TPG hold 50% of the new company and paid $35M for that. This means the total Aptina valuation is about $70M.

Another possibility is that employees stock options are accounted as a future dilution, so Riverwood and TPG paid $35M for 65% of Aptina stock. In that case the total valuation of Aptina would be $54M. In both cases it's much lower than Omnivision's valuation. Am I missing something?

Correction: After discussing it with a reg. accountant it's clear to me that without knowing the exact amount of cash taken from and given to Aptina there is no chance to calculate the company value, not even approximately.