FORTUNE -- Facebook (fb) is largely credited with the widespread popularity of trading in private company shares, and arguably has seen more of its stock trade via secondary markets than all other private companies combined.
The question, therefore, is whether those pre-IPO buyers got a good deal.
According to data released this morning by SecondMarket, it would seem they did. At least most of them.
SecondMarket reports that it first was contacted by a Facebook employee about selling stock back in early 2008, when the shares were valued at just $3.50 each. Once the SecondMarket platform actually launched one year later, FB shares only were valued at between $1 and $2 each.
Then it seriously began to climb. By the end of 2010 it was at $21.32 per share. Last year it breached $30 by March, rising as high as $34.14 in July before settling back at $30.38 in December. Just before the company filed for its IPO this past April, the shares were trading at $42.72.
It's worth noting that SecondMarket rival SharesPost closed some auctions at $44 per share, and that the institutional pricing typically was cheaper than individual pricing (particularly over the past several months).
Around 50% of Facebook buyers through SecondMarket are described as "asset managers" or hedge fund managers. Individuals make up 14.8% of the pie, while family offices (11.8%) and mutual funds (7.5%) also are represented. The vast majority of transactions came in 2011, with a particular spike when it became conventional wisdom that the company would go public in 2012.
Approximately 79% of sellers described as former Facebook employees. Around 12.4% were existing Facebook investors, including angels.
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