NEW YORK (

TheStreet

) --

Facebook

(FB) - Get Report

was a big loser in premarket trading on Thursday as the social networker prepares to report its first quarterly results as a public company.

The Menlo Park, Calif.-based firm, which made an

eventful IPO

in May, slipped 5.83% to $27.63 ahead of its second-quarter results. Facebook, which reports after market close, is also one of the most active premarket

Nasdaq

stocks on share volume of 923,400.

Analysts surveyed by

Thomson Reuters

are looking for Facebook to report revenue of $1.15 billion and earnings of 12 cents a share.

Facebook partner

Zynga

(ZNGA) - Get Report

, however, is an even bigger laggard, tumbling 40.33% to $3.03 after its weak

second-quarter earnings report

on Wednesday.

The social gamer, which derives a significant portion of its revenue from Facebook, reported second-quarter earnings of 1 cent a share on $332 million in revenue. Analysts surveyed by

Thomson Reuters

were looking for earnings of 6 cents a share and revenue of $344.85 million.

Zynga is also the most active premarket Nasdaq stock on share volume of 4,432,187.

Hard drive maker

Western Digital

(WDC) - Get Report

is a big gainer, rising 17.03% to $38 after reporting strong fourth-quarter results and offering robust guidance on Wednesday.

Western Digital's beat also boosted rival

Seagate

(STX) - Get Report

, pushing the company's shares up 12.5% to $29.60 before market open. Seagate, which reported certain preliminary numbers earlier this month, reports its full fourth-quarter results on Monday.

Security specialist

Fortinet

(FTNT) - Get Report

is another winner on Thursday, rising 12.51% to $25.19 as investors respond positively to the company's healthy

second-quarter results

on Wednesday.

TheStreet

will be live-blogging Facebook's second-quarter results at 3.45 PM ET:

--Written by James Rogers in New York.

Follow @jamesjrogers

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