Retail investors in Hewlett- Packard are due to hear this week from a leading US shareholder advisory firm whether they should back the merger with Compaq, as the outcome of the controversial deal approaches its endgame.

Institutional Shareholder Services, a proxy advisory firm, is due to recommend perhaps as early as today whether shareholders should back the merger. Its opinion is expected to have a crucial bearing on the outcome.

By one fund manager's calculation, Hewlett-Packard must secure the support of at least 70 per cent of the institutional shareholders who have not voiced an opinion.