BlackRock to Auction Amazon Seller Once Valued at $1 Billion (1)

BlackRock Inc.has initiated an auction for German startup SellerX, taking the unusually aggressive step after a loan granted to the Amazon aggregator soured.

An advertisement published Friday in the Börsen-Zeitung newspaper stated that the auction for the L Catterton-backed firm has been scheduled for Sept. 17 at a Berlin hotel. In Germany, such auctions can be used by creditors to seize control of companies after negotiations between an enterprise, investors and lenders have hit an impasse, often wiping out equity held by investors.

The move is evidence of an accelerating shakeout among companies known as aggregators that raised billions ...