(Reuters) - Shares of Rubrik ( RBRK ) fell more than 6% on Tuesday, as the markets braced for the expiry of a lockup period tied to its initial public offering, clouding the Microsoft ( MSFT )-backed cybersecurity company's upbeat second-quarter revenue.

The lockup period expires on Wednesday and typically that would allow company insiders and pre-IPO investors to sell their shares, which often puts pressure on the stock price.

Rubrik's ( RBRK ) results, the second after it went public in April, indicate that businesses have been spending heavily to shield themselves from growing cyber attacks that have hit companies, including UnitedHealth Group, Microsoft ( MSFT ) and U.S. oilfield services firm Halliburton.

"While the pending IPO share-lockup expiry on Sept. 11 could cause some downward share price pressure, this report and the current robust cybersecurity spending environment confirm our positive Rubrik ( RBRK ) thesis," brokerage CIBC wrote in a note.

If losses hold, Rubrik ( RBRK ) will be on track to shed more than $350 million. The company had a market valuation of $5.77 billion as of Monday's close.

California-based Rubrik ( RBRK ) reported second-quarter revenue of about $205 million, compared with analysts' average estimate of $196.2 million, according to LSEG data.

Its adjusted loss per share for the quarter was 40 cents, compared with the estimates of a loss of 49 cents per share.

"We have helped hundreds of customers quickly come back online after the recent global IT disruption," Chief Executive Bipul Sinha said on a post-earnings call on Monday.