Twitter says it's only considering CEO candidates who can make a 'full-time' commitment

Jack Dorsey would have to give up his post at Square if he's to become CEO of Twitter.

The company he helped found and now leads on an interim basis said Monday that it is only considering candidates who can make a "full-time commitment to Twitter."

Dorsey was named interim CEO after Dick Costolo stepped down effective July 1 amid criticism over Twitter's disappointing financial performance and share price decline. Costolo had been Twitter's CEO for five years and led the company through a successful stock market debut in 2013. But Twitter has yet to make a profit and there are concerns about its ability to grow its user base.

Peter Currie, chair of Twitter's search committee, says the company is looking for a "bold thinker and proven leader."