If you listen closely, you might be able to hear something that sounds like the continents shifting and grinding together, deep under the earth’s crust. Is there an earthquake coming? No, that’s just the sound of massive piles of cash being moved—the vast sums of money that Uber and its Chinese rival Didi Chuxing are stockpiling for their battle to own the global ride-hailing market.

Just a couple of weeks ago, Uber raised $3.5 billion in financing from the investment fund belonging to Saudi Arabia’s royal family as part of a total financing worth $5 billion, one of the largest funding rounds ever raised by a venture-backed company. That investment brought the total raised by Uber to more than $10 billion, and gave it a theoretical market value of about $62 billion.

Now there are reports that Uber is raising as much as $2 billion more, but this time it is doing so via the debt market, a somewhat more risky endeavor than the equity or venture-capital markets. One reason it may be doing so is to avoid diluting its existing equity value for existing investors, in advance of a possible initial public offering of stock next year. A debt issue of this kind also means it doesn’t have to publicly release its financial information.

Not to be outdone, Didi Chuxing just finished raising $7 billion in funding from a group of investors that includes Apple and China’s top life insurance company. The round consisted of $4.5 billion in equity funding and $2.5 billion in debt, and gives the Uber competitor a theoretical market value of about $28 billion.

But Didi’s strongest card in this rapidly accelerating game of automotive chicken may not be its growing cash hoard. The company, which was created last year by the merger of two competing taxi-hailing apps, also has some extremely powerful local investors—including China’s e-commerce giant Alibaba and its social-networking behemoth Tencent. Both reportedly put money into the latest round, and they clearly have the resources to finance a significant battle. Start your engines.