(Yicai Global) Jan. 9 -- Xiaomi's shares plunged to a record low today as the six-month lockup period following the smartphone maker's initial public offering ended and despite controlling shareholders pledging not to dispose of their stock for a further 12 months.

As more than 3 billion shares, or about 19 percent of those outstanding, were unlocked today, Xiaomi [HKG:1810] fell more than 6.8 percent to close at HKD10.34 (USD1.32). The benchmark Hang Seng Index gained 2.3 percent.

Founder and Chairman Lei Jun, Smart Mobile Holdings and Smart Player -- the firm's controlling shareholders -- have voluntarily agreed not to sell directly or indirectly for another 365 days, the Beijing-based company said in a stock exchange filing this morning. They hold 31 percent of the firm's equity.

The lock-up period prevented some employees and cornerstone investors from selling their allocated shares, which are down almost 40 percent from their Hong Kong IPO price of HKD17 each amid a wider selloff in Chinese equities.

Xiaomi could come under further pressure if early venture capital and private equity investors decide to trim their stakes in the company, said Tang Chuan, an analysts at Sinolink Securities. It held nine rounds of preferred stock financing from September 2010 to December 2014, raising USD1.6 billion. It is about time VC shareholders made an exit, Tang added.

Chief financial officer Zhou Shouzi has also agreed not to sell his shares for a year, the filing revealed, even though he's not one of the top 10 shareholders. No similar undertaking from President Lin Bin, who has an 11 percent stake, appeared in the statement.

Xiaomi has acquired a small stake in electrical appliances maker TCL, Guangdong province-based TCL said in a statement on Jan. 6, and the two firms have agreed to work together on developing smart products. The news led to a nearly 10 percent jump in TCL shares [SHE:000100]. Xiaomi's investors have not been so fortunate.