US stocks rallied&nbsp; yesterday snapping a three-day losing streak, as a spurt of corporate takeovers in the technology and health-care sectors fuelled optimism about share values.<br /><br />Mergers and acquisitions are typically viewed as bullish as it suggests companies are more optimistic about the business outlook.<br /><br />A number of deals were announced and investors bet more could follow. Xerox&nbsp; agreed to buy Affiliated Computer Services, and Abbott Laboratories said it would pay $6.6bn for Solvay&rsquo;s drug unit.<br /><br />The Dow Jones industrial average rose 124.17 points, or 1.28 per cent, to end at 9,789.36. The Standard &amp; Poor&rsquo;s 500 Index gained 18.60 points, or 1.78 per cent, to 1,062.98. The Nasdaq Composite Index shot up 39.82 points, or 1.90 per cent, to 2,130.74.<br /><br />With yesterday&rsquo;s gains, the Dow Jones industrial average held an advance of about 16 per cent in the quarter so far, making it the index&rsquo;s best such period since the fourth quarter of 1998.<br /><br />But the end of the third quarter on Wednesday may spur volatility as fund managers&nbsp; sell laggards in favour of out performers to spruce up portfolios at quarter&rsquo;s end.<br /><br />In the last three sessions, the S&amp;P 500 had declined more than 2 per cent after rallying nearly 60 per cent from the 12-year year closing low of early March.