SAN FRANCISCO (AP) -- With oil prices surging and U.S. stock prices slumping, chip maker Advanced Micro Devices Inc.'s sale of an 8.1 percent stake to the Abu Dhabi government's investment arm represents the latest plunge by a wealthy Middle Eastern nation into a troubled U.S. corporation.

It also raises fresh questions about the appropriateness of Middle Eastern firms owning large chunks of U.S. businesses that specialize in advanced technologies.

Sunnyvale-based AMD, the world's No. 2 microprocessor maker, needs the $622 million investment from the Mubadala Development Company to help lift the company out of a deep financial slump.

AMD has lost more than $1.6 billion so far this year, and has just $1.5 billion in cash on hand as it works to pay down $5.3 billion in debt. The financial woes have caused AMD's stock to fall more than 35 percent since the start of the year, a slide that has wiped out nearly $4 billion in shareholder wealth.

The infusion, announced Friday, is a necessary jolt for AMD is it hunts for money to fund its counteroffensive against Intel Corp., the world's largest chip maker, and amid a huge spike in investments

SAN FRANCISCO (AP) -- Cisco Systems Inc. has boosted its stock buyback effort by $10 billion, a sign the Internet networking supplier still believes its shares are undervalued.

The move, announced Friday, is a way for the San Jose-based company to increase the value of remaining investors' stakes, counter the effect of employees exercising stock options and protect its financial image.

When stock options are exercised, it adds shares to the market, while a buyback removes them and boosts the value of each remaining shareholder's stake.

Cisco's decision highlights the dilemma many companies face in trying to reduce the dilution caused by generous employee stock option plans.

Cisco, the world's largest maker of Internet routers and switches, has been profiting from steadily rising demand for more Internet bandwidth and sophisticated networking gear to handle an influx of voice, video and data content on the Web.

Since Cisco launched its stock buyback program in September 2001, it has been on a tear and seeking for

Trying to time your purchases and sales of mutual funds is often a fool's errand. For one thing, it may not be necessary. That's because investors don't need to worry about buying or selling following a run of good performance, at least in theory; after all, the fund manager should be selling securities that are overvalued and replacing them with ones that are undervalued. That's an oversimplification, of course, but it gets to the appeal of actively managed mutual funds. Further, the delayed reporting of a fund's portfolio and a high level of trading actively make it tricky to say with much conviction whether a fund's portfolio is undervalued or overvalued at any one point in time.

Nonetheless, anyone who is investing a big lump sum in a fund might rightly consider whether a fund's holdings are reasonably or richly valued, and an investor who's about to sell would do well to do the same. It's not impossible to assess whether a fund portfolio is over- or undervalued, presuming a fund has consistently low portfolio turnover, using Morningstar's estimates of each holding's fair value. The exercise can also be employed when analyzing exchange-traded funds and index funds, which have largely static portfolios. But we'll save those for another day.

To start, I simply compared the stock prices of different fund portfolio holdings with Morningstar's fair