"We initiate at underperform considering where we are in the cycle, our expectation of deterioration in returns and their rich valuations," said Bernstein in a client note. "One cannot give the same multiple to a business built on the premise of a regulatory arbitrage."
Waaree shares fell 4.2% to ?2,279.8 and Premier declined 2.2% to ?889.8 on Wednesday.
Bernstein said Waaree and Premier face the risk of deep-pocketed bigger groups entering the space.
"We think this will eventually be a place for the big players with backward integration - Reliance, Adani Enterprises etc.- to lead," said the brokerage. "While Waaree does show the potential to join this league, and is rightly exploring avenues beyond the module-cell, we think the key competitors have much bigger wallets to compete."
"It's too early to dismiss them, but at the valuations they trade it - we think it already prices in them joining the big boys club."