>> From what I gather, Archegos had $10B of equity in total? Typically (sensibly) you don't put all your eggs in one basket as a fund, even a quite concentrated fund.

>> How big was the position?

I think you're trying to get to "how was the loss so big?" The size of the position is only part of the answer.

The other comments answer the size of the position. But there are several other factors here.

They probably liquidated too late -- they ended up liquidating with giant block trades. That unwind also cost a lot because the block trade is at a discount to market value. Further, the larger the unwind, the bigger the price hit you take.

Finally, these types of unwinds can spook others in the market and further drive down the price.