Five9 (FIVN) shares took a sharp 5.07% dive during Friday's intraday trading, a surprising turn of events that left investors puzzled. The plunge came on the heels of what initially appeared to be positive news, with the company raising its full-year profit and revenue forecasts.

Earlier in the day, Five9 had seen its shares rise in pre-market trading, with increases of 6.5% and 4.9% reported at different times. The company's improved financial outlook had initially buoyed investor sentiment. However, the tide turned dramatically as the regular trading session progressed.

The catalyst for this reversal appears to be a significant target price cut by Truist Securities. The financial services firm slashed its price target for Five9 from $65 to $40, a move that seemingly overshadowed the company's optimistic forecasts. This substantial reduction in the expected value of Five9 shares likely triggered a wave of selling, leading to the observed 5.07% decline.