"There are concerns over competition from Facebook entering what has pretty much been Trade Me's domain for a period of time," McIntyre said.
"We're seeing movement on brisk volume, and you'd have to suspect there have been offshore moves in that stock as well, moving money away, for such a dramatic drop."
Infratil declined 2.5 per cent to $2.96, Summerset Group Holdings fell 1.7 per cent to $4.61 and Orion Health Group dropped 1.6 per cent to $3.15.
Port of Tauranga was unchanged at $3.80. It expects full-year earnings in the range of $79 million to $83 million, an increase on the $77.3 million reported for 2016, according to a transcript of a speech published to the NZX.
Sky Network Television rose 0.4 per cent to $4.78. Chief executive John Fellet hit out at submissions opposing the pay-television broadcaster's planned $3.44 billion merger with Vodafone at its annual meeting yesterday. Fellet said the merger was on track, with the Commerce Commission not yet changing its November 11 target date for a decision.
Metro Performance Glass was the best performer, up 1.9 per cent to $2.16, something McIntyre said could be the result of Fletcher Building presenting to investors and talking up the strong construction sector.
Spark rose 1.9 per cent to $3.52, Auckland International Airport gained 1.7 per cent to $6.72 and Chorus advanced 1.6 per cent to $3.72.
Outside the benchmark index, Wynyard Group was unchanged at 21.5c. The crime-fighting and intelligence software company yesterday extended its trading halt until Tuesday as it seeks to tap a $10 million stand-by loan facility agreed with Skipton Building Society in August.
Childrenswear retailer Pumpkin Patch plunged 16.7 per cent to 6c. The shares fell on the deadline for directors to propose measures to address its capital constraints with lender ANZ. The constraints were highlighted in its full-year accounts as a "material risk" to the ongoing viability of the business.