NEW YORK—Despite having been a partner at the prestigious Manhattan law firm since 1984, Martin Kline is still not sure he fits in at Oppendahl, Oppendahl, Kline & Oppendahl LLP. "I don't know," the 53-year-old corporate-finance specialist said Monday. "I mean, sure, Bill, Larry, and Dan [Oppendahl] treat me like one of their own. But for some reason, I just somehow feel different. No matter how many contracts I draw up or hours I bill, I still don't quite feel like I belong."