Barnard Marcus achieved one of its best results of recent months in London on 14 November, with an initial total of £22m and a success rate of 71%, which it expects to increase to around 80% with post-auction sales.
More than half of the 166 lots were sold in the room and 27 sold prior.
The October sale raised £21.6m from 155 lots, with a success rate of 71%.
Seven lots of garages and land being sold by the London Borough of Waltham Forest off a combined guide price of £102,000 achieved a total of £319,000.
Six ground rents sold for a total of £515,000, which is nearly 40 times the rental income.
A vacant flat in Battersea, SW11, being sold by the London Borough of Wandsworth, sold for £622,000 off a guide of £530,000. A freehold semi-detached house in a hamlet near Reading, Berkshire, guided at £400,000, sold for £522,000.
Auctioneer Chris Glenn said the increase in stamp duty earlier this year had affected the market.
“The whole situation with stamp duty has bitten a few people. Novice buy-to-let buyers are looking at their tax bills,” he said. “It has cooled the market far too quickly. The only thing people can do is charge more rent, and there is clear evidence that rent inflation is on its way.
“It will take people currently renting a lot longer to get a deposit together.”
The sale took place at the Grand Connaught Rooms, WC2, on 14 November.