Which of the following is a violation of semi-strong form (but not weak form) efficiency? Returns tend to drift upwards for takeover targets prior to the takeover's first public announcement. Following positive unemployment news announcements, market returns tend to go up for the next 5 trading days. Stocks with high returns in the past three months tend to outperform firms with low returns in the past three months over the following 3-12 months. More innovative firms tend to earn higher returns