Clearwire (Nasdaq: CLWR) is running out of sugar daddies.

Time Warner Cable (NYSE: TWC) is unloading its 7.8% stake in the mobile network operator. According to SEC filings, Time Warner exchanged all 46 million of its Class B Clearwire shares for Class A stock. That move is an obvious preparation for selling off Time Warner's interests in Clearwire, since there is no market for Class B interests but Class A stubs can be traded on the NASDAQ.

So the entire load of not-so-restricted Class A shares is presumably for sale on the open market now.

Time Warner still holds a small, indirect interest in Clearwire through regional cable subsidiary Bright House Networks, which owns 8.5 million Class B shares for a 0.6% stake of the company's total votes. Sprint Nextel (NYSE: S) remains the largest Clearwire investor by far, owning 48.3% of the votes outright.

But Sprint considered giving up 77 million shares in the second quarter and Google (Nasdaq: GOOG) liquidated its entire load of 29 million shares in the first quarter. Like I said: Clearwire is running out of rich friends.

And it's not like Clearwire couldn't use some investor cash at the moment. The company is busy supplementing its WiMax 4G network with another operation based on the competing LTE 4G standard. All that hardware is expensive. For now, Clearwire can only commit to supporting LTE phones in "densely populated urban areas." The rest of the country will have to wait until Clearwire can afford to go there.

Oppenheimer analyst Timothy Horan notes that Time Warner cares less about Clearwire's network now that the cable company has an agreement with Verizon (NYSE: VZ) in place. "We ultimately believe that Sprint will gain control," Horan says, but the dilution from such a takeover is not accounted for in Clearwire's current price.

In other words, look out below even after Tuesday's 12% price drop. Shares have plunged 41% over the last 12 months, but the bottom still lies ahead.

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