Venture capital funds have poured close to $2 billion into cannabis startups this year, and mainstream funds are slowly getting more comfortable with cannabis tech companies. But that's at the early stages. For later-stage cannabis companies, it's still challenging to raise growth capital. Top investors say they are still wary of investing in cannabis and cannabis-related companies since valuations are high and THC is federally illegal. Click here for more BI Prime stories, and subscribe to our weekly cannabis newsletter, Cultivated.