The pessimistic lenders typically predicted a fall of more than 2.5 per cent according to the report, with just 8 per cent of lenders expecting values to rise.
Lenders were similarly concerned when it comes to residential property, with almost two thirds (61 per cent) forecasting a fall.
The political situation was cited by three-quarters (74 per cent) of respondents, with Brexit (51 per cent) by far the biggest concern.
The study found that lenders were looking to bigger ticket purchases, reserving some of the best pricing for these larger transactions.
It found that the maximum loan amount had jumped sharply for investors, from an average of £134m in 2017 to £154m last year and now all the way up to £226m.
It noted there were now five lender categories which will lend a maximum of £500m or more on investment loans: North American banks, pension funds, debt funds, insurance companies, and Pfandbrief banks.
James Wright, head of real estate finance at Link Asset Services, said that confidence has turned to caution, with Brexit weighing heavily on the market.
“We are seeing many taking a far more cautious approach as a result, with fewer expecting to do more business, and many falling back into their core markets and products.
“It looks like, in the next 12 months, we’ll see lenders take a ‘softly, softly’ approach until there is greater clarity around the UK’s relationship with the EU, and economic and political fears calm,” he concluded.