Shares of hydrogen technology provider Plug Power are at it again.

Plug stock traded as high as $4.58, a new 52-week high, before sliding back to $4.13, up 8.4% on Monday. The S&P 500 rose 0.4% and the Dow Jones Industrial Average fell 0.1%. The move came after Plug stock rose 67% this past week.

The gains started with progress for the business. Shares jumped 26% on Wednesday after the company said it delivered its first 10-megawatt GenEco electrolyzer array to Galp, a Portuguese energy company.

Electrolyzers use electricity and water to make hydrogen, a green fuel that creates no carbon dioxide, the main gas blamed for climate change, when burned or used in a fuel cell. If the electricity used to make hydrogen is generated from renewable sources, no carbon dioxide is generated along the value chain.

Plug stock soared 34% on Friday after H.C. Wainwright analyst Amit Dayal raised his price target to $7 from $3, noting that higher electricity prices help make hydrogen technology more competitive. He now expects Plug Power to generate revenue of $11 billion in 2035, up from $7 billion previously.

Dayal rates shares Buy. Overall, 28% of the analysts covering the company rate shares Buy, according to FactSet. The average Buy-rating ratio for stocks in the S&P 500 is about 55%. The average analyst price target for Plug stock is about $2.33.

Monday’s rise appears to be a continuation of the recent rally. There aren’t any new analyst actions or news releases from the company.

Plug isn’t profitable yet, and shares are heavily shorted, which is a recipe for stock market volatility.

Bearish investors will borrow stock they don’t own and sell it, hoping prices will decline. When prices start to rise rapidly, it can spook short sellers who rush to buy, adding fuel to any rally. About 40% of the stock available for trading has been sold short, according to FactSet. That is more than 10 times the average short interest for a stock in the S&P 500.

Coming into Monday trading, Plug stock was up 212% over the past six months, leaving shares up 79% year to date.

Where shares go next is anyone’s guess. Plug stock now trades for about 5 times estimated 2026 sales, up from about 1 times sales a few months ago.