Barclays and four of its traders have been fined $453m (£300m) by United States regulators for manipulating power prices.
In a fresh blow for the scandal-hit bank, the Federal Energy Regulatory Commission (FERC) also ordered the lender to pay at least $34.9m (£23m) of “unjust profits” to the low-income home energy assistance programmes of Arizona, California, Oregon and Washington. FERC, which upheld fines first imposed last October, accused Barclays and its traders of a “co-ordinated and intentional effort” to fix electricity prices in California and other western US states between November 2006 and December 2008.
It has given the bank 30 days to pay the fines.
Barclays vowed it would “vigorously defend this matter”.
FERC said the level of the fines reflected the “seriousness of the violations and the lack of any effort by Barclays and the traders to remedy their violations”.
As well as a $435m (£288m) fine against Barclays, FERC has ordered Scott Connelly, then managing director of North American power at the bank, to pay $15m (£9.9m), while fellow traders Daniel Brin, Karen Levine and Ryan Smith must each pay $1m (£662,000).
FERC said it had found a trail of emails and instant messages that revealed the power price rigging. FERC alleges that Barclays manipulated the electricity market for a total of 655 days, costing other firms nearly $140m (£93m) by driving power prices up and down to the benefit of derivatives positions held by the bank.
The fine comes as Barclays is already battling to repair its image in the wake of its £290m Libor rigging scandal last summer, which claimed the scalp of former chief executive Bob Diamond.