June 8 (Reuters) - Cerebras shares gained on Monday as multiple Wall Street firms initiated coverage with bullish calls after the quiet period, backing the chip designer's unconventional AI strategy more than three weeks after its strong debut.

Shares of the company CBRS.O rose 5.5% in premarket trading, with at least nine brokerages — including IPO bookrunners Morgan Stanley, Citigroup, Barclays and UBS — initiating coverage of the stock.

The California-based firm designs wafer-scale engine chips roughly the size of a dinner plate to speed up processing, challenging traditional GPU-based systems, like those of Nvidia NVDA.O, that rely on clusters of interconnected chips.

"As AI workloads become increasingly reasoning-intensive, demand for fast, low-latency inference is growing rapidly," said Morgan Stanley analysts led by Joseph Moore, who rate the stock "overweight".

"This is a unique chance to invest in an AI processor company with a first-mover advantage against Nvidia, and offers substantial upside as the category evolves."

Citigroup expects Cerebras' shares to hit $340 in the next 12 months, according to LSEG-compiled data.

IPO underwriters can publish research on a stock 25 days after listing.

Cerebras counts Amazon.com AMZN.O and Sam Altman's OpenAI as customers and is also backed by the ChatGPT maker and Japanese investment giant SoftBank 9984.T. The latter reportedly sought to take the chip designer private before its debut.

Cerebras debuted on the tech-heavy Nasdaq .IXIC more than three weeks ago and closed about 70% above its initial public offering price of $185.

However, its shares have since lost about 36%, as of last close, on concerns the global tech rally had run too far, while investors also priced in hawkish Federal Reserve monetary policy for the rest of the year amid the Middle East conflict.

The Philadelphia SE Semiconductor Index .SOX is up 60% this quarter, on track for its biggest quarterly gain since January 2000.