Early Prime Day Deals Roe v. Wade Overturned Surface Laptop Go 2 Review 4th of July Sales M2 MacBook Pro Deals Healthy Meal Delivery Best TVs for Every Budget Noise-Canceling Earbuds Dip to $100

SoftBank, not Mayer, should run Yahoo, investor says

Alternative Investment Management & Research pictures a Yahoo-SoftBank merger, with the latter's CEO running the combined company.

Steady drumbeat of worry and complaints that has marked Yahoo's recent history is back. James Martin/CNET

Yahoo CEO Marissa Mayer is again under fire from an investor that believes she may not be the person to lead the company.

Alternative Investment Management & Research, an investor in Yahoo, issued a letter to the company on Monday urging Mayer to explore the possibility of merging with Japanese telecomunications copmany SoftBank, according to Bloomberg, which obtained a copy of the letter. The letter was also sent to SoftBank CEO Masayoshi Son.

"We think that Yahoo would be far better off under the stewardship and vision of Mr. Son than under Yahoo's current top management," Alternative Investment Management & Research managing director Albert Saporta wrote in the letter, according to Bloomberg. "We would rather have Mr. Son in charge of investing Yahoo's cash hoard."

Yahoo did not immediately respond to a request for comment.

Alternative Investment's letter is just the latest in a string of complaints that have hit Yahoo over the last several years. Mayer was appointed chief executive in 2010, around the same time many activist investors were pushing the board to make a sale. Her appointment kept investors quiet for some time, and her many acquisitions -- including the $1.1 billion acquisition of blogging platform Tumblr -- hinted that major changes were afoot. But the steady drumbeat of worry and complaints that has marked Yahoo's recent history is back.

Just last week, Starboard Value, an activist investor, wrote an open letter to Mayer saying that Yahoo should acquire AOL. The investor argued that the tie-up between AOL and Yahoo would allow for a more efficient online advertising model and help both companies improve their position in a space dominated by Google.

At the core of these comments is money Yahoo made during Alibaba's initial public offering earlier this month. After selling more than 6 percent of its stake in Alibaba in the Chinese company's massive IPO, Yahoo is due a windfall of $8.27 billion before taxes -- giving it ample cash to do what it wants. Yahoo has already promised to return at least half the Alibaba proceeds to shareholders, but what it will do with the rest is unknown at this point.

In its letter, Alternative argues that SoftBank CEO Son would do a better job of managing Yahoo's cash hoard, according to Bloomberg. Under his leadership, SoftBank, which provides both mobile and Internet services to customers in Japan and elsewhere around the world, has grown considerably. For its fiscal year ended March 2014, the company generated 527 billion yen in profit ($4.8 billion). SoftBank owns a majority stake in Sprint, the third-largest wireless carrier in the US, and it has a partnership in place with Yahoo Japan.