One of Twitter's biggest bulls is making a bold call on improving user growth.
MKM Partners analyst Rob Sanderson has a buy rating on Twitter and 12-month price target of $61, representing more than a 60% rally.
"I think this is the year where we start to see product improvement turn the trajectory of user growth. If that's correct, I think there will be a pretty meaningful revaluation of the stock higher," Sanderson said on CNBC's "Fast Money Halftime Report."
Twitter's revenue growth is stronger than Facebook's was during its first quarter's as a public company, according to Sanderson.
"Twitter is outpacing Facebook revenue growth. Growth rates are much higher with directional correlation for every quarter on record," Sanderson wrote in a note to clients.
Twitter CEO Dick Costolo's future lies within user growth, Sanderson said.
"If we turn around and start to see more accelerated growth in 2015 then he's considered a good CEO. If he doesn't, he will probably be shown the door," Sanderson said.