US regulators have upheld a fine on Barclays and four of its traders of $453m (£300m) for allegedly manipulating electricity prices.
Barclays must pay $435m within 30 days, while one trader must pay $15m and three others $1m each.
Barclays must also forgo $34.9m in profits, which will be distributed to low-income aid programmes in Arizona, California, Oregon and Washington.
Barclays said it intended to “vigorously defend this matter”.
The fines were first proposed by staff at the Federal Energy Regulatory Commission (FERC) last October, and have now been upheld by the body’s board of commissioners.
FERC accused Barclays of manipulating the electricity markets in California and other states from November 2006 to December 2008.
A page from the Enron playbook, no doubt.