Heavily indebted JA Solar Holdings Co Ltd (JASO.O), which has lost nearly a third of its market value this year, said it could buy back up to $100 million of its shares before the end of September, sending the stock up 25 percent.
Other China-based solar companies such as LDK Solar Co LDK.N, Yingli Green Energy Holding (YGE.N) and ReneSola Ltd (SOL.N) have also been buying back shares amid a brutal selloff in the stock market.
"We believe a share buyback is not where solar companies should spend their cash; and see the (JA Solar) rally as overdone," Jefferies & Co analysts, who rate the stock "underperform", wrote in a note.
"We recommend investors take profit."
Based on JA Solar's closing price of 93 cents on Wednesday, the company can buy back up to 107.5 million shares, or more than half its current outstanding.
The company, the world's third-largest maker of solar cells, had long-term bank borrowings of 4.35 billion yuan ($683 million) at the end of last year. About 885 million yuan worth of loans were due in 2012.
Thiemo Lang, a senior portfolio manager at Zurich-based Sustainable Asset Management, said the buyback will help push up JA Solar's stock in the short term, but he does not expect other Chinese companies to follow suit given their high debt level.
"JA Solar must make sure it reaches profitability again soon, which is still more than uncertain in the current environment," he said.
The Shanghai-based company posted losses for the last four quarters as product prices tanked due to falling renewable energy subsidies in top European markets.
Analysts expect the company to return to a profit only in 2014, according to Thomson Reuters I/B/E/S.
Of the 15 analysts covering the company, five recommend a "sell" or a "strong sell", while nine rate it "hold", according to Thomson Reuters data.
JA Solar and its top lenders, state-owned Export-Import Bank Of China EXIMC.UL and Bank of China Ltd (601988.SS), could not be reached for comment outside of regular business hours in China.
"The company's lenders may not appreciate this news as much as (their) equity investors will," Raymond James analyst Alex Morris wrote in an email.
Chinese solar companies raked up huge debts in the last two years as they expanded rapidly, helping the Asian country become the largest producer of solar cells in the world.
Western solar companies have complained that cheap loans from state-run banks have helped Chinese firms sell their products at cheaper prices.
Last month, the United States imposed duties of 31 percent on solar panel imports, ruling in favor of local companies that accused Chinese firms of dumping.
"We hope JA Solar finds ways to extend its debt maturities, but this may be difficult because credit has become increasingly tight in China," Simmons & Co analysts wrote in a note.
JA Solar shares rose to a one-month high of $1.16 on Thursday on the Nasdaq.
The WilderHill Clean Energy index .ECO, which has fallen about 17 percent this year, inched up 0.18 percent to 42.98 points.
($1 = 6.3691 Chinese yuan)
(Reporting by Krishna N. Das in Bangalore; Editing by Viraj Nair, Sreejiraj Eluvangal, Saumyadeb Chakrabarty)