LONDON, June 1 (Reuters) - The pool of negative-yielding euro zone government bonds shrank in May to its lowest in a year, as brighter economic prospects pushed up borrowing costs across the bloc, Tradeweb data showed on Tuesday.
Tradeweb said the market value of negative-yield euro-denominated government bonds traded on its platform stood at around 5.3 trillion euros ($6.48 trillion) as of end-May in a total market worth almost 9 trillion euros.
That accounted for around 59% of the total market, a touch lower than 60% at end-April and the lowest share in a year.
The market value of British gilts on the Tradeweb platform with negative yields stood at around 651 billion pounds ($923 billion) at the end of May, or 26% of a total market worth around 2.5 trillion pounds. That share of negative-yielding UK debt was broadly unchanged from a month earlier.
Tradeweb data also showed a 1.2 trillion-euro pool of negative-yielding euro-denominated investment grade paper -- roughly 36% of a total 3.5 trillion euro market at the end of May. This was a touch lower compared to the previous month. (Reporting by Dhara Ranasinghe; Editing by Saikat Chatterjee)