In a massive bet on Internet video, China’s Alibaba announced today it has made a $4.2 billion bid to acquire Youku Tudou.

The move is not entirely shocking. Last year, Alibaba invested $1.22 billion in the company, which offers a YouTube-like service in China.

That gave Alibaba and its investment partner, Yunfeng Capital, an 18.5 percent stake each in Youku Tudou.

Now, facing its own concerns about slowing growth, Alibaba is grabbing the rest of the company.

“We believe that the proposed transaction, with tighter integration of our resources, will help Youku achieve exciting growth in the years ahead,” said Alibaba chief executive Daniel Zhang in a statement.

The deal must still be approved by Youku Tudou’s shareholders, though it has the support of the company’s founders.

Alibaba wants to pay $26.60 per Youku Tudou share to get the 82 percent of the company it doesn’t own. That values the company at $5.2 billion, a 30 percent premium over its market cap from yesterday of $3.99 billion.