Meet the Man Cracking Down on the LIBOR Scandal Brendan Smialowski / Getty Images It's been a bad week for banking - and the next few weeks and months will likely get worse. With new arrests in London, the investigations over manipulation of LIBOR - the London interbank lending rate that is central to the global financial system - are heating up again. And the driving force behind the crackdown is Gary Gensler, chairman of the U.S. Commodity Futures Trading Commission (CFTC), who years ago helped loosen the rules for Wall Street but has since become its toughest cop. When he's not busy putting the heat on traders and brokers accused of rigging rates to benefit themselves and their firms, Gensler is a pretty genial guy. The 55-year-old single father laughs easily, jokes frequently, and - in between sober reflections on his role in making our financial system safer - tells self-deprecating stories about the perils and joys of raising three daughters (Anna, 22; Lee, 21; and Isabel, 16) on his own following the death of wife Francesca in 2006. Gensler opened up to TIME about all that and much more, in an exclusive interview at his home in Baltimore (to read TIME's profile of him, pick up this week's issue, available to subscribers here). The interview sheds new light on what still needs to be cleaned up in global markets, and on the man who's leading the charge. MORE: Guess Where Banks Are Sticking Their Fine Print Now? Since last summer, Gensler has been a central figure in exposing the biggest banking scandal since the financial crisis - the LIBOR interest-rate manipulation investigations. LIBOR is an arcane term for a simple concept: the interest rate that a bank might charge another bank. You may not pay much attention to it, but LIBOR plays a huge role in lots of everyday loans, since banks use it as a benchmark to set other rates. Adjustable-rate mortgages, many student loans, and car payments are pegged to LIBOR. So are countless complex financial instruments, including 70% of the U.S. futures market. In all, LIBOR underlies some $350 trillion worth of derivatives contracts and $10 trillion in loans. So the notion that someone has played games with LIBOR doesn't sit well with Gensler, to say the least. From pro investors making giant bets to homeowners considering a refinancing, practically everyone in the market relies on the assumption that the LIBOR benchmark reflects reality. "These rates are at the absolute core of our global financial system," he says. If they are falsely reported, "that goes to the integrity of markets and how much trust the public has in them." MORE: Good News: Young Americans on the Move Again It turns out that public trust was indeed misplaced. On June 27, after four years of investigation by the CFTC, Barclays became the first major bank to publicly admit that it had been rigging the rates it submitted for LIBOR for years, paying $450 million in fines as a result. More than a dozen other global banks are under investigation by the CFTC and other U.S. and European regulators for falsely reporting or manipulating LIBOR. A number of those banks have been setting aside massive reserves to deal with potential fines. UBS, which may end up paying even bigger penalties than Barclays, has socked away some $610 million to deal with possible regulatory issues. To read more about what else may be coming down the financial pike, and how the LIBOR scandal developed, pick up this week's issue of TIME magazine.