Shares of Zillow Inc (Z) fell as much as 10% after Securities and Exchange Commission staff asked the real estate website for more disclosures in its quarterly and annual reports.

The SEC staff and questioned why the company, which provides housing price appraisals called "Zestimates,'' was unable to disclose the percentage rise in prices for premium subscriptions.

Zillow had said it was unable to provide the information due to wide variations in prices, which are based on zipcodes. "It would seem that such information would also be meaningful to investors,'' said the SEC staff in its correspondence with the company.

Zillow acknowledged that these disclosures may be meaningful to investors and said it would begin evaluating and disclosing these numbers.

Short-seller Citron Research said last month that Zillow does not have revenue transparency in its business model.

Shares of the company, which fell nearly 9% on Sept. 25 after the Citron report, were down 5 at $38.69 on Tuesday on the Nasdaq. They had touched a low of $36.66 earlier.

"It is a knee-jerk reaction,'' PAA Research analyst Bradley Safalow said of the Tuesday's share fall. "But when you actually read the document, there is nothing nefarious in the original correspondence. None whatsoever.''

The SEC staff investigate and recommend action that is then voted on by the SEC commissioners. He said Zillow was a high-multiple stock and investors have a tendency to react to correspondence with the SEC.