Shares of anti identity theft service LifeLock fell almost 18 percent on Monday after the company said it was temporarily suspending its iOS and Android apps because it may have failed to adequately secure user data.

The stock price closed down $2.28, or 17.6 percent, to $10.70 on the New York Stock Exchange Monday. The sell-off was triggered by LifeLock's move late last week to delete all information stored on its servers by the Wallet mobile applications for iOS and Android devices. LifeLock, which acquired the apps in December for about $42.6 million, also pulled them from the Apple App Store and Google Play Market. The company took the unusual steps after determining that unspecified aspects of the apps "may not be fully compliant with payment card industry (PCI) security standards" that are binding on most merchants who accept payments through credit or debit cards.

"We know we’re asking a lot of our LifeLock Wallet users—to delete and go without this application for a period of time," CEO Todd Davis wrote in a blog post published Friday. "I personally apologize for the inconvenience. At the same time, I want to make sure that when LifeLock Wallet is available again, you’ll know that you can download it, provide your personal information, and use it again with confidence—knowing that it’s backed by an industry leader that is committed to doing the right thing and taking care of its customers." The company, which said there's no indication that any data has been maliciously compromised, issued an accompanying statement to shareholders at the same time.

Friday's disclosure isn't the first time LifeLock practices or management have come under close scrutiny. In 2010, the company agreed to pay $12 million to the FTC and 35 states to settle charges that it used false claims to promote its identity theft prevention services. It also follows revelations that Davis' identity has been misappropriated numerous times over the years despite ads promoting the effectiveness of LifeLock services by displaying his Social Security number on the side of a truck.