At the time Nortel Networks filed for bankruptcy protection in 2009, no one foresaw the biggest stand-alone patent sale to date coming out of that process.

But Cleary Gottlieb Steen & Hamil­ton’s creation of a unique bankruptcy auction system last summer for some 6,000 Nortel patents not only netted $4.5 billion last July — more than five times a $900 million stalking-horse bid by Google offered in April 2011 — but became a wakeup call for boardrooms to take a fresh look at the potential value in their sleepy patent portfolios.