Top executives remain confident, a survey said.

According to the survey by the Conference Board, a business-sponsored research group, executives remained fairly confident about the economy during the second quarter of this year. Of the 1,000 top executives questioned, more than two-fifths thought that business conditions had improved in their industries, and half expected conditions to strengthen in the second half of 1986. However, the survey was taken in May and early June, before the release of recent government and industry indicators showing a sluggish economy.