Chinese equities capped their biggest weekly rally since 2008 with a burst of trading that overwhelmed the Shanghai stock exchange, underscoring a dramatic shift in investor sentiment after Xi Jinping’s government ramped up economic stimulus.

In an echo of the rally that followed China’s massive stimulus during the global financial crisis, the CSI 300 Index of large-cap shares soared 4.5 percent on Friday — bringing this week’s gain to 16 percent. Trading activity was so intense that it led to glitches and delays in processing orders, according to people familiar with the matter. The Shanghai exchange said it was investigating the issues, without elaborating.

It was a frenzied end to a week that has raised hopes of a bottom in China’s $8.9 trillion stock market after years of losses that made it one of the world’s worst performers. Chinese authorities unleashed a long hoped-for barrage of monetary stimulus on Tuesday, followed by vows from top leaders to do what’s necessary to shore up the housing market and boost consumption.

While many details of China’s stimulus plan remain unclear and past bouts of euphoria have often fizzled, market watchers say the fear of missing out on a sustained rally is palpable. With China’s markets closed next week for the Golden Week holidays, domestic investors may be worried that the rally could continue in Hong Kong while they’re away, said David Chao, a strategist at Invesco Asset Management.

“FOMO is running high for investors as Chinese equities have moved close to 10% in the past three days,” he said. “Based on historical valuation, we think Chinese stocks have another 20% runway to go.”

A gauge of Chinese stocks in Hong Kong climbed 3 percent, notching its longest winning streak since 2018. The ChiNext index, a tech-heavy gauge, rose a record 10 percent. Turnover in the mainland topped 1.4 trillion yuan ($200 billion), to reach the highest in three years, despite the trading issues. Turnover in Hong Kong reached 445 billion Hong Kong Dollars ($57.2 billion), the highest on record. Meanwhile, Chinese companies listed in the US were poised to extend gains at the open as they rallied in premarket trading on Friday.

As investors turned to risk assets over havens, China’s ultra-long government bond futures saw their biggest daily loss on record Friday. China’s 10-year bond yield rose 5 basis points at 2.16 percent.

The rally also severely hit a number of quantitative hedge funds in China, people familiar with the matter said. Some firms suffered losses because they shorted index futures for their so-called Direct Market Access strategies, said the people, asking not to be identified discussing a private matter. In some cases, the losses were exacerbated by the exchange glitch that left them unable to sell holdings to meet margin requirements, another person said.

Chinese authorities’ shift this week drove billionaire investor David Tepper to declare that he’s buying more of “everything” related to the country. “I thought that what the Fed did last week would lead to China easing, and I didn’t know that they were going to bring out the big guns like they did,” he said in a CNBC interview Thursday. “We got a little bit longer, more Chinese stocks.”

The securities regulator’s guidelines to encourage companies to attract long-term investors also fortified the optimism already brewing in the market.

The broad rally Friday was underscored by 266 of the CSI 300 Index’s 300 members ending the day in the green, with spirits maker Kweichow Moutai Co. and battery producer Contemporary Amperex Technology Co. leading the surge.

But Chinese bank stocks bucked the rally and fell, as investors weighed the implications of a 1 trillion yuan ($142 billion) capital injection plan reported by Bloomberg News. China is planning to inject funds mainly raised from the issuance of new special sovereign bonds, the report said, citing people familiar with the matter.

The injection plan could lead to a 56 basis point dilution of return on equity, JPMorgan analysts including Katherine Lei wrote in a note. The slump may also a reflect a shift away from sectors that were viewed as more resilient when the market was falling; with some of the nation’s highest dividend yields, Chinese banks have appealed to investors looking for stable returns.

Some investors are looking for signs of more fiscal stimulus to drive the next leg of gains. “We can expect fiscal measures as well to come,” said Raymond Chen, a fund manager at ZiZhou Investment Asset Management. “This is for sure leaving many cynics behind.”

Morgan Stanley is among a slew of China watchers gradually turning bullish, with strategist Laura Wang and her colleagues seeing another 10 percent upside for the CSI 300 Index in the short term. Just days earlier, the Wall Street bank removed its preference for onshore stocks over offshore counterparts, citing a lack of supportive factors such as state buying.

The optimism also drove higher other Asian stocks with exposure to the world’s second-biggest economy as the risk-on mood intensified across the region.