Sometime in the last week or so, we&'ve heard from multiple sources, Accel Partners has sold very significant chunks of Facebook stock. So significant, in fact, that their ownership percentage has dropped to a point where they are no longer the largest venture shareholder in the company.

Prior to the sale they had somewhere around 10% of Facebook. They paid just $12.7 million for that stock, in 2005. Our understanding is they sold somewhere around 20% of that position, meaning they own 8% or so of Facebook now.

So who bought it, and what was the price

One source said TCV purchased some $200 million of the stock. And another source says Andreessen Horowitz purchased $80 million in Facebook stock out of their massive new fund.

The price A year ago Elevation Partners bought $90 million in Facebook stock at a roughly $9 billion valuation. Then earlier this year they invested $120 million more at a $14 billion valuation.

We&'ve heard these current trades occurred at a $35 billion valuation from one source. Another said $40 billion, and yet a third said &''way lower.&'' Whatever the price, it&'s likely half a billion dollars or more that Accel is taking off the table. Our guess is the valuation is somewhere between $20 billion and $35 billion.

To be clear, we haven&'t confirmed some of this. But it&'s pretty clear Accel is selling a lot of Facebook stock right now, and that at least Andreessen Horowitz is one of the buyers &8211' they confirmed to us that they have begun buying shares, but won&'t comment on price or number.

Update: More information from a new source with knowledge of the deal. Accel has sold a substantial amount of stock Something less than 20% of their total holdings, and the sale(s) are occurring at a $35 billion enterprise valuation. That&'s a 247x return on Accel&'s initial investment. Our best guess is it was total sale of around $500 million. It&'s still unclear if Accel or DST is now the largest venture shareholder of Facebook.

Andreessen Horowitz confirmed that they purchased stock from Accel, but it was just a fraction of the total stock sold by Accel.

It&'s also worth noting that Accel Partner Jim Breyer&'s personal stake in Facebook is worth some $350,000,000 (minus dilution for subsequent venture rounds and employees since 2005) at this new valuation. He purchased 1% of Facebook for himself at the time Accel invested. Not a bad day at the office.