They might've been up in smoke earlier this year but marijuana stocks could be something to keep an eye on heading into the summer.

The new Ancillary Pot Stocks Index tracks the performance of 16 companies that provide goods and services to cannabis companies and complements the Pure-Play American MSO Pot Stocks Index and the Pure-Play Canadian LP Pot Stocks Index. 

Most sector commentators and marijuana ETFs include marijuana-related stocks in their approach to the sector which conveys a distorted picture of the health of the sector.

NewCannabisVentures has launched an Ancillary Cannabis Index that tracks the performance of 14 companies providing goods and services to cannabis operators.

The major benchmarks are mixed midday, as investors await U.S. President Joe Biden's infrastructure spending "Build Back Better" plan.