Editor’s note: A version of this post by Yin Yi first appeared on Yicai Global, the English-language financial news service of Shanghai Media Group. Yicai Global is one of just two dedicated Chinese news feeds connected to the Bloomberg terminal.

China’s three major bitcoin trading platforms — Huobi.com, Okcoin.cn, and Btcchina.com — are ending a withdrawal freeze after upgrading anti-money laundering systems.

OKCoin started testing withdrawals on May 31, allowing customers to take out up to 20 bitcoin and 200 litecoin a day, the platform told Yicai Global. Huobi resumed withdrawals on June 1, allowing users to pull out a maximum of 50 bitcoin per day. Btcchina said it will resume withdrawals after its new risk control system passes tests.

Bitcoin prices on these platforms have soared more than 25 percent to over CNY20,000 since May 31.

Chinese bitcoin exchanges have put very strict anti-money laundering and know your customer measures in place following four months of scrutiny and overhauls, bitcoin insiders told Yicai Global.

Regulators are mainly worried about situations that have the potential to get out of control — not just with the platforms, but also with bitcoin features such as anonymity, global liquidity, and volatility, said Deng Di, director of China Blockchain Research Center.

“However, regulators will also take into account that a number of countries including Japan and India have provided policy support to promote the healthy development of bitcoin and will leave room for new things to develop,” Deng said.

Trades denominated in Japanese yen and US dollar each accounted for 30 percent of the latest global bitcoin transactions, while yuan-denominated transactions made up 16.8 percent, per the latest data from Huobi’s blockchain research department.

China’s central bank held talks with bitcoin trading platforms including Huobi, Btcchina and OKCoin in January. The Big Three suspended Bitcoin and litecoin withdrawals shortly thereafter.