NEW YORK ( TheStreet) -- Facebook ( FB) 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), 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) 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), 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) 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 >To submit a news tip, send an email to: firstname.lastname@example.org. Check out our new tech blog, Tech Trends. Follow TheStreet Tech on your wireless devices.