While debt-crippled Chinese firm Evergrande has struggled to repay bondholders and investors, shares of the real estate developer tumbled on Thursday.

Evergrande, drowning in $300 billion in liabilities, did not pay offshore coupons due earlier this week after becoming ensnared in Beijing's deleveraging crackdown on China's bloated property sector.

Earlier this week the group cheered investors by insisting it would be able to deliver tens of thousands of units this month and pay off some debts.

But shares plummeted Thursday after Bloomberg News said the due date had passed for two more debt deadlines with no sign of payment, wiping out earlier gains this week.

Evergrande, whose $19 billion in international bonds are in cross-default after missing a deadline to pay coupons earlier this month, had new coupon payments worth $255 million due on Tuesday for its June 2023 and 2025 notes.

Some bondholders holding the two bonds have not yet received the coupons, according to three sources with knowledge of the matter. Both the payments have a 30-day grace period.

By late Thursday morning, shares were down 10.30% on the Hong Kong stock exchange.

The embattled developer was already labeled as being in default by international rating firms earlier this month after it failed to repay liabilities on time.

Earlier struggles to pay suppliers and contractors due to the debt crisis led to sustained protests from homebuyers and investors at the group's Shenzhen headquarters in September.

In recent months, the company has repeatedly said it will finish its unfinished projects and deliver them to buyers in a desperate bid to salvage its debts, despite having missed the earlier payment of more than $1.2 billion.

At a company meeting Sunday, Chairperson Hui Ka Yan, known as Xu Jiayin in Mandarin, said that since the company's troubles began, they delivered fewer than 10,000 units in September, October and November.

"There are only five days left this month. We must charge full steam ahead to guarantee the delivery of 39,000 units this month," he said, according to a statement.

The bloated firm has tried to sell off its assets and shave down its stakes in other firms, with Hui paying off some of the debts using his own considerable personal wealth.

The provincial government of Guangdong – where the firm is headquartered – is currently overseeing Evergrande's debt restructuring process.