Facebook shares accounted for 39 percent of SecondMarket's transactions in the fourth quarter.
Trading in securities related to consumer products and services dominates SecondMarket's activity. Clean technology, meanwhile, accounts for 2.5 percent of SecondMarket activity, perhaps revealing that the "green" fad is over.
The seller composition shifted dramatically in December, as current employees of companies cashed out in far greater proportion than they had in prior months.
The majority of share sales came from companies with employee bases larger than 500.
There were more sellers than buyers in every category except consumer products and services, SecondMarket's bread and butter. In that domain, buy-side demand by far outstripped sell-side demand.
Brooklyn-based companies accounted for 5 percent of trades, trailing Palo Alto and Mountain View. Brooklyn Stand Up!
SecondMarket activity has gone vertical since 2008.
New York tech companies Foursquare and Meetup are among SecondMarket's featured "newbies."
SecondMarket also measures "votes" for popular companies, and DropBox grew fastest in popularity, up 100 percent from the third quarter.