Markit said it could mean funds were either hedging or shorting the stock.
In February, Capco admitted sales had ground to a halt on the second phase of its Lillie Square flats complex in Earls Court. Its shares have slumped almost 20% this year, making a killing for short-sellers.
Capco, led by Ian Hawksworth, declined to comment on the increase in short-selling.
It comes amid concerns about a glut of homes in parts of the capital, with inflated prices and new stamp duty rises on buy-to-let homes scaring off potential buyers, especially from overseas.
Last month, Morgan Stanley warned prices of new, upmarket London flats could fall by as much as 20% this year, meaning Capco might delay pre-sales until the market has improved.
Liberum’s David Brockton suggested Sadiq Khan’s plan to make half of new homes in the capital “genuinely affordable” if he becomes mayor could also have contributed to the rise in Capco short positions. “Sadiq is on record as having reservations about the direction of Earls Court,” the analyst said.
Simon Stone, the Candy brothers’ former right-hand man and head of Stone Real Estate, said many people in the industry are blaming the stamp duty changes for pricing pressure.
“Many new-build developments rely heavily on buy-to-let investors, so the further increases which came into place last week could add further unwelcome pressure,” he said.
At Berkeley, short bets trebled in the past month and account for £250 million, or 6%, of shares rather than 2% previously. The FTSE 100 group which is behind the Riverlight development in Nine Elms, has attracted short-sellers since February. Crispin Odey’s firm Odey Asset Management has the largest short stake at 1.2% worth £55 million.
