Henderson Global Investors' shareholders have received an unsolicited offer to sell their shares well below market value from an Australian businesswoman Suzanne Lee Forster.

Forster who has made the offer through her own firm Hassle Free Share Sales is offering to buy the shares through the firm's Australian listing at a price of A$1.01. At close of business in Sydney on Thursday the shares were trading at A$2.19.

Forster has a record of gaining access to shareholder registers in order to make offers to small shareholders well below the trading price in the hope that they will accept without realising the value the offer represents.

Yates said: 'We are concerned about the type of offer Ms Forster has made to our shareholders. This offer is significantly below the current value of Henderson Group and should therefore be rejected by shareholders.

'We urge shareholders to seek independent advice; they should check the terms of the offer and the price of Henderson Group shares before taking action on any unsoliicted offers to buy their shares.'

Meanwhile in London Henderson shares have been falling by 8.28am they were trading at 105p, a drop of some 6.87%.