I don't know about Shylock HOLMES, but i do know that Shylock was a character in one of Shakespear's plays (The Merchant of Venice). He was a Jewish usurer, so saying that a person is a Shylock means he's a loan shark.
You shouldn't mess with the guys down on 57th, they're real shylocks and the interest rates will kill you.
Pseudonym of a blogger of undisclosed identity who sounds off about various matters -- economic, political, social, sexual -- at the blog "The Adventures of Shylock Holmes." The dude (definitely male) sounds educated, a bit smart-alecky, conservative with a heart (sometimes). Not American -- his spelling is weird. Prolly a rich kid waitin to make a name for himself.