LONDON (Reuters) - The owner of London's landmark "Can of Ham" building has rejected a higher offer from Blackstone of about 330 million pounds ($426.92 million) for the property, with Nuveen betting on an improving appetite for European real estate assets, a source close to the matter said.

The 21-storey building at 70 St Mary's Axe is one of the few big-ticket office properties put up for sale in Europe in the past few years after the market was hit by post-pandemic changing working patterns and higher borrowing costs.

The "Can of Ham" sale is one of several in Europe being tracked as a test of whether buyers and sellers can agree on price after office sale volumes slumped last year to their lowest level since 2009.

The latest talks between Blackstone and Nuveen over the tower broke down over the price, the source told Reuters, asking not to be named in connection with non-public information.

Blackstone had already had a 300 million pound offer for the building refused last year, Reuters reported.

Blackstone and Nuveen declined to comment.

Blackstone's new offer exceeded the 322 million pound price tag Nuveen wanted when it put the tower on the market last year. But Nuveen has since revised up its expectations, the source said, encouraged by robust leasing activity in London and cash returning to European assets more generally.

Nuveen wants a higher price and could choose to hold on to the building to see how market conditions play out, the source said. It had previously attempted to sell the building for around 400 million pounds in 2022.

Investors globally have begun warming again to the highest-quality office properties from New York to London, as companies call employees back to the office and a lack of new buildings leads to a potential supply crunch.

But there have been very few large office sales in Europe. Brookfield delayed a sale of its London Citypoint tower after bids fell short, forcing it to extend debt repayments, Reuters reported in January.

($1 = 0.7762 pounds)

($1 = 0.7730 pounds)