ValueAct Capital Management, the activist fund run by Jeffrey Ubben, plans to return $1.25 billion to investors in May because of concerns that company valuations are expensive. San Francisco-based ValueAct, which manages more than $16 billion, explained its decision to return capital in a letter last week to investors that was viewed by Bloomberg News. It said that current prices on companies the firm follows “can only be justified by assuming cyclically high corporate margins will persist, a certainty of lower corporate taxes and a risk-free rate that stays near all time lows.” Hedge fund managers have expressed opposing views on...