Lyft (LYFT) investors are seeking a clearer view of US organic growth rates following the overall 330-basis-point Q2 rides acceleration, as the Canadian market nearly doubled year over year, recent acquisitions boosted growth into Q2 and Q3, and the World Cup provided a Q2 bump, RBC Capital Markets said in a note.

The company's management pointed to less-dense markets, premium rides and ramping partnerships as evidence that the US is a "solid" growth market, according to the note.

RBC further said it estimates partner-linked rides grew by about 33 million in Q2 versus overall rides growth of 28 million, including acquisitions, and thus investor feedback likely reflects "the desire for more comfort with the underlying organic growth rate to support the stock's multiple."

RBC has an Outperform rating on Lyft and a $20 price target.

Price: 17.35, Change: +0.13, Percent Change: +0.73