The on to $150 euphoria over the IBM Corp share price was hit late last week and early this by profit-taking, and was firmly squelched on Tuesday by a note from PaineWebber Inc analyst Stephen Smith, who downgraded his rating on the company’s shares to attractive from buy, and lowered his 1991 earnings estimate to $10.90 a share from $11.25 against the $10.51 a share of 1990. The two factors he thinks will inject a worm into the IBM rose – and indeed bouncing technology stocks generally is an international survey forecasting a major slowdown in overseas computer demand, with the spending index down to 2.8 in January compared with 4.6 in October, the lowest for three years. And with dollar stabilisation, the dollar effect is likely to be diminished in the second half.