The world’s largest asset manager is threatening to unleash a fresh wave of shareholder rebellions in the UK unless Britain’s largest companies rein in excessive boardroom pay. BlackRock is demanding cuts to director pension entitlements and an end to huge pay rises as UK companies prepare to put their latest pay deals to shareholders. In a letter to the bosses of more than 300 UK companies, the US fund manager said it would only approve salary rises for top executives if firms increase workers’ wages by a similar amount. It is a significant intervention from a company which is a shareholder in every business listed on the FTSE 100 index. BlackRock has USD5.1 trillion of investments and describes itself as the world’s largest fund manager. The company’s head of investment stewardship in Europe, Amra Balic, said in the letter that a failure to meet the standards outlined by the fund manager would call into question the quality of the board.