Could This Be The Mystery Treasury Bidder?

Remember the mystery of the big Treasury auction bidder(s) that this correspondent covered in a past life? A big buyer (or buyers) that didn't fit into normal categories started showing up at auctions last year, and bidding up two-year notes. Since that story was published, the buyer(s) have bought more than $25bn of two-year and three-year notes, with more than $15bn of that amount in two-year floating-rate securities.