Regulators investigating traders in Libor case

Welcome to the morning roundup. Here's a look at today's banking and finance news.

Libor probe expands. Regulators are investigating several groups of traders for allegedly conspiring to rig interest rates, people close to the probe told the Wall Street Journal. The criminal and civil investigation includes more than a dozen traders from at least nine banks, the Journal writes.

Internal rate-rigging investigation. An internal probe at Deutsche Bank found two former traders might have collaborated to manipulate benchmark interest rates, but there was no indication of failure at the top of the company, Reuters reports, citing people close to the investigation.

Subprime rally. U.S. home-loan securities without government backing are rallying as investors bet the housing bust is over and bond dealers snap up supply, Bloomberg reports. Securities backed by option adjustable-rate mortgages jumped 7 percent in the past month to the highest level since May 2011, for instance.

London Whale. Trading spikes that temporarily boosted the value of credit derivatives held by JPMorgan Chase & Co. might offer clues about whether traders there masked big losses, Bloomberg reports. The surges came right before monthly bank audits to verify prices.

European debt. Signs of trouble in Europe persist, with markets falling Monday amid doubts about Greece's ability to make its debt payments and intense pressure on Spain's economy, the New York Times reports. In recent years, August has brought financial turmoil for Europe - and this year, "all signs again point to a nerve-wracking end of summer," the Times writes.