US coal mining giant Peabody Energy (NYSE: BTU) boosted its bid for Australia’s Macarthur Coal (ASX: MCC) to $3.8 billion from an original bid of $3 billion.

In addition to increasing its offer for Macarthur Coal, Peabody Energy indicated that it’s looking for a controlling interest in Macarthur but would be willing to allow the firm’s three major shareholders to maintain their economic interest if they so wish. Macarthur’s three biggest shareholders are Chinese state-owned investment company CITIC Group, which holds a 22.4 percent stake, and steelmakers ArcelorMittal (NYSE: MT) and Posco (NYSE: PKX, Seoul: 005490), which hold 16.6 and 8.3 percent stakes, respectively.

Normally, when a company makes an acquisition bid, the stock sells off a bit in the short run. But this has yet to occur to shares of Peabody, suggesting that investors generally like the miner’s attempts enhance its competitive position in Australia.  Clearly, the Chinese recognize the strategic importance of Macarthur’s reserves; state-owned CITIC is the largest single investor.

Two other companies I’ll be watching closely are Australia’s Gloucester Coal (ASX: GCL) and New Hope Corp (ASX: NHC). Macarthur had been planning to acquire Gloucester but may need to cancel or delay that deal as it considers Peabody’s bid. New Hope is competing with Peabody to buy Macarthur. Peabody Energy remains a buy up to 52.