Henderson, M&G and Standard Life Investments have switched from (higher) 'offer' to (lower) 'mid' or 'bid' pricing on their commercial property funds, which effectively reduces the value of funds by between 5 per cent and 6.25 per cent.
Those who exit the funds will therefore get less for their holdings than would have previously been the case.
Each firm told investors that the move was in response to an anticipated increase in outflows, ahead of the EU referendum that takes place on 23 June. The fund management firms are concerned there may be a rush to the exits in the event of the British public deciding to leave the EU.
Some investors have already sold ahead in anticipation of this scenario playing out. In the first three months of the year the Investment Association's property sector recorded net outflows each month.
In response, the three firms have decided to prevent existing investors being disadvantaged by the negative impact of transaction costs on the fund value.
This occurs when outflows increase because although property funds now keep significant cash buffers to protect against such a situation some of the fund's property assets may also need to be sold to give investors their money back if there is a sustained sell-off.
By switching the pricing, which lowers the fund's value, the fund groups say sellers will bear the transaction costs, rather than investors who remain in the fund.
Patrick Connolly, a financial planner at Chase de Vere, says: 'Over the last couple of years commercial property funds have been extremely popular, but this is beginning to change, especially with the Brexit vote on the horizon.
'As a result fund groups, in switching their fund prices from offer to bid, are making sure that investors who remain in the fund should not bear the cost of any asset sales that have to be made.'
The move could be a temporary one, however, if the UK votes to remain part of the EU and investors return to the sector.