BlackRock (BLK.US) saw its stock decline sharply during Friday's trading session, falling nearly 7% at one point. By the time of writing, the shares were down more than 5%, trading at $973.42. The drop follows a disclosure in a fourth-quarter filing from TCP Capital Corp., a subsidiary of BlackRock, which revealed that a $25 million loan extended to Infinite Commerce Holdings has been written down to zero. Infinite Commerce is an "Amazon aggregator" that acquires and operates online sellers offering a wide range of products, from spa items to light bulbs. As recently as the third quarter of last year, BlackRock had valued this subordinated debt at 100% of its face value. Due to the deterioration in asset quality, BlackRock TCP reduced its quarterly dividend from 25 cents per share to 17 cents and also wrote down part of its investment related to SellerX. In the filing, BlackRock TCP indicated that 91% of the valuation markdowns within its portfolio stem from transactions originated in 2021 or earlier, with these assets coming under pressure amid the current high interest rate environment.