Worldwide, as much as 0 trillion worth of financial products are tied to the London Interbank Offered Rate, or LIBOR. So it was no small concern this spring when some experts questioned whether the rate’s daily updates were rigged to be artificially low. Set LIBOR rates too low and borrowers might get an undeserved windfall — at lenders’ expense. “I think this is potentially a major issue,” said Wharton finance professor Jeremy Siegel , adding: “We’re talking about the biggest benchmark for short-term loans in the world.” Wharton finance professor Franklin Allen said the process for setting LIBOR rates is “probably accurate most of the time. But some of the time it may deviate.” Questions this spring centered on whether some of the 16 banks that contribute data to the LIBOR calculation were reporting lower-than-actual figures to ease doubts about their own financial health. The first concerns were raised by some banking experts in April.…