Alibaba finally filed with the SEC for a U.S. IPO Tuesday afternoon. The company is likely to have a major following as its shares hit the market for the first time, and it may even set a record for the biggest offering of all time. For now, however, the company’s IPO is set to have a large impact on one more familiar name.

There are few shareholders in Alibaba right now. Three entities own around 70 percent of the company, including Japanese powerhouse Softbank, founder Jack Ma and the struggling internet advertiser Yahoo! Inc. (NASDAQ:YHOO). Yahoo, which has been led by CEO Marissa Mayer for close to two years, is set to earn a massive cash influx on Alibaba’s IPO day, and what it does with the money is of prime interest to investors.

Yahoo Value Rests On Alibaba Growth

For the past couple of years, the astounding returns in Yahoo stock have not come from Marissa Mayer’s handling of the company, though her executive style probably helped. Investors have been interested in owning Yahoo stock as an indirect way of getting exposure to the Alibaba growth story. Yahoo owns about 23 percent of the company, a stake that could be worth around $38.4 billion on IPO day if current valuations are correct.

Yahoo says it’s going to get rid of 40 percent of its shares in Alibaba when it is first offered to the public. That leaves Yahoo with a greatly reduced position in the company, and a cash inflow that will dominate the firm’s decision-making process. With the engine of growth related to Alibaba mostly removed on IPO day, Marissa Mayer will have to discover another way to make Yahoo grow.

That won’t be easy. The company’s business has been declining for years, and it’s only since Mayer took over that its user numbers and sales have stabilized. That leaves the company well behind competitors Google Inc (NASDAQ:GOOG) and Facebook Inc. (NASDAQ:FB), and the cash influx from Alibaba’s IPO will not be able to compete with the war chests of those companies.

Alibaba IPO Is A Yahoo Watershed

Mayer has made big changes as CEO of Yahoo, but the executive has not yet gotten the company around to acceptable profitability. With Alibaba cash at her disposal, she will have to make decisions that grow the company or face losing the faith of her investors. Yahoo stock is likely to suffer if the company’s strategy is not clear.

Mayer had the best possible start to her career at Yahoo. Alibaba, a business that did not require her direct management, supplied the company’s core with enough cash to keep operating, while she tried to turn the company around from the inside. That grace period is coming to an end this summer, and the executive will have to show that her attempts to turn Yahoo around have really made the company into a profit-builder. Otherwise investors are going to be unhappy with a post-Alibaba IPO Yahoo.

Disclosure: The author has no position in the stocks mentioned in this article, and does not intend to initiate any position in the next 48 hours.