Yesterday's poor 30-year Treasury auction reverberated through the market but later in the day, many people were arguing that it should be ignored because a ransomware attack kept China's largest bank -- ICBC -- out of bidding.

Yellen now says there was no impact on the Treasury market from the attack. Could she mean that there's been no direct impact?

Whatever happened, US 30-year yields are back to where they were before the sale.

US 30s
US 30s, 5 min chart