Guidance was revised to 50-55 bps over US Treasuries from 70-75 bps over Treasuries earlier in the day, according to the document from one of the banks on the deal, which is expected to launch later in the day.
Ten-year gilt yields rose as high as 0.868%, up 6 basis points on the day, to their highest since March 18, in line with the rise in yields for 10-year US debt.
"The number of new COVID-19 cases is rising rapidly, and an extension of the lockdown inevitable for many European countries. No one will be surprised by such a decision," said Milan Cutkovic, market analyst at Axi.
MSCI's gauge of stocks across the globe shed 0.04%, with slight gains in Europe but a 2.1% decline in Japan's Nikkei index.
The Fed said it would, however, launch a formal review of the capital rule, known as the "supplementary leverage ratio," due to concerns it is no longer functioning as intended as a result of the central bank's emergency COVID-19 pandemic monetary policy measures.
"Wall Street bank stocks will get punished because now they will have to put more money aside," Edward Moya, senior market analyst at foreign exchange brokerage Oanda, said in an email.
Euro zone yields were already edging down, tracking moves in US Treasuries, which were affected by an auction of benchmark 10-year notes that was not as bad as feared.
The ECB barely increased its emergency bond purchases in recent weeks, stoking doubts about the bank's resolve to calm market nerves and support indebted governments through the pandemic.
Yields are down from their highs this week, but pressure remains. US Treasury yields rose on Wednesday, alongside euro area government bond yields and UK gilts, pushing stock markets and other low-yielding safe assets lower on Thursday.
Italian bond yields were last unchanged, pushing up the gap between 10-year Italian and German yields a touch higher to around 104 bps.
"We should not hesitate to increase the volume of purchases and to spend the entire PEPP envelope or more if needed," Panetta said in a speech.
Just under 1 trillion euros ($1.20 trillion) of the ECB's PEPP quota is still unused and until the recent yield rise, policymakers argued that the ECB did not necessarily have to spend this amount.
But analysts expect the premium to drop as the United States embarks on renewed economic stimulus and as Chinese authorities pledge to continue supporting the economy with ample liquidity.
"Fears of (People's Bank of China) de-leveraging could trigger the correction of China equities, and discourage capital inflow for China stock markets," said Mizuho's chief Asian FX strategist Ken Cheung.
The kingdom on Tuesday sold $2.75 billion in 12-year bonds at 130 basis points (bps) over 10-year US Treasuries and $2.25 billion in 40-year notes at 3.45%.
It drew more than $13 billion in orders for the 12-year bonds and over $9 billion in orders for the 40-year paper.
At the shorter end of the market, the two-year JGB yield fell half a basis point to minus 0.140%, while the five-year yield was unchanged at minus 0.110%.