Alliance Trust may be faced with more hostile corporate action after a US hedge fund declared a 10% stake.
Share buybacks carried out by Venture Capital Trusts (VCT) will no longer qualify for tax relief from April 2014, the government has said.
The board of Anthony Bolton's Fidelity China Special Situations fund has bought back a further 750,000 shares in a bid to narrow its discount.
News Corporation has moved to shore up its share price with a $5bn stock repurchase programme.
Manager sees little interest to be earned from cash, believing buybacks would be more beneficial to investors