Many of Groupon’s private stock sales are in the red.

Groupon  GRPN shares are still trading above last month’s IPO price, but are well below where they were trading on private secondary markets over the summer.

Companies like Groupon are not required to publicly report their private share sale prices, and secondary exchange SecondMarket was prohibited from releasing Groupon data because it participated in the IPO underwriting syndicate (via a partnership with Morgan Stanley).

But a source has stepped up with some relevant data.

He tells Fortune that SecondMarket only brokered one Groupon trade before the original S-1 was filed on June 2, 2011. That was at around a $7 billion valuation. Between June and August, Groupon shares changed hands multiple times at a $18 billion valuation. It then began to dip down again shortly before the pricing (likely due to the relentless press criticism), although I don’t have exact numbers.

For context, Groupon priced its IPO at a $12.65 billion valuation, and opened trading today at around $14.7 billion.

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