The maintenance of a Buy rating suggests that UBS still sees Arch Capital Group as a good investment, but the reduction in the price target could imply a reassessment of the potential growth or a response to market conditions. This news is likely to be taken positively by investors, as the Buy rating is reaffirmed, but the lower price target may temper expectations slightly. The impact on the stock price is likely to be neutral in the short term as the positive and negative aspects of the news may balance each other out.