Updated below: At the rate it is going, $15 per share might sound enticing to Yahoo (NSDQ: YHOO) after a while. A small Yahoo investor Mithras Capital has put out a proposal asking MSFT to rebid for the company at $22 a share, reports Reuters. As part of a proposed deal, Microsoft (NSDQ: MSFT) would unload Yahoo’s Asian assets and non-search businesses, extract $3 billion worth of cost savings and receive $2.8 billion of tax benefits, which means MSFT will pay $10.3 billion for Yahoo’s search business (about $2 billion less than it was willing to pay earlier in the summer for search portion). It also calls for Yahoo to drop its poison pill, while valuing Yahoo’s Asian assets at $7.2 billion and its non-search business at $4.5 billion. Earlier this year Mithras backed Carl Icahn’s stake in the company.

Yahoo’s shares hit a five year low yesterday, and today is down about 2 percent today to trade below $13. The Yahoo-Google (NSDQ: GOOG) ad deal is certainly going to be mired in regulatory issues in a while, and any Yahoo-AOL (NYSE: TWX) combination would also face somewhat similar regulatory issues.

Update: The shares dipped below $12 today, though they are above that mark now.

Staci adds: Meanwhile, according to an SEC filing (pdf), Yahoo investor Capital Research Global Investors has upped its stake to 10.1 percent, using the down market to add its holdings. The fund held 8.6 percent when it reported on June 30. Together with sibling Capital World Investors, the funds have a stake of 22.34 percent.