Warren Buffett's right-hand man and business partner, Charlie Munger, offers this advice for successful investing: "Carefully look at what other great investors have done." Luckily for us, great investors are required to divulge changes they make to their portfolios on a quarterly basis. These SEC 13-F filings allow us to peek into the stock comings and goings of money pros, including multibillion-dollar hedge fund manager Ken Fisher.

Let's take a closer look at investments Fisher gave pink slips to this past quarter. I zeroed in on a couple of stocks that Fisher completely sold out of and a few in which he reduced his position but still holds.

Dumped
Diamond Foods (DMND.DL) was poised to acquire Pringles from Procter & Gamble last year but lost the brand to Kellogg. The deal would've added the popular potato-chip brand to Diamond's existing product lineup of Kettle Chips, Pop Secret, and Emerald Nuts. Ultimately, that deal fell though because of accounting problems, which had Diamond shifting payments to walnut growers into future quarters and falsely inflating profit margins. Diamond Foods' stock lost nearly 58% last year. Fisher probably saw the writing on the wall and took the loss for 2012.

Shares of PSS World Medical (NASDAQ: PSSI) skyrocketed in late October after it was announced that McKesson would acquire PSS in the first quarter of 2013 for nearly $1.5 billion. The all-cash deal values PSS at $29 per share. The 32% bump in PSS's share price (up to $28.57)  on Oct. 25 probably enticed Fisher to sell out of his stake in the company completely.

Dialed back
Several years ago, Las Vegas Sands (LVS -0.78%) doubled down on gaming properties in Macau, a bet that's paid off handsomely. But further slowing growth in China may impede progress. Las Vegas Sands is looking to expand in Spain, a country with widespread unemployment and an established gaming industry. Fisher sold nearly all of his Las Vegas Sands stock in the third quarter of 2012, but he dumped even more in the most recent quarter.

Fisher reduced his position in drug maker Celgene (CELG) during the fourth quarter. Of course, that occurred before the company's announcement earlier this month that it projects sales to double in the next five years. Since that Jan. 7 announcement, its stock has rallied 16%. Despite projecting slowing sales for its Revlimid drug, Celgene claims a number of growth drivers for 2013 and beyond.

The hedge fund manager also dumped more than 80% of his stake in the nation's largest natural-foods supermarket chain, Whole Foods Market (WFM). The company intends to ramp up new store expansion, which slowed considerably through the economic downturn. And Whole Foods is benefiting from its exposure to higher-income households, as they've held up much better than lower-income consumers during the most recent recession.

Foolish bottom line
I don't own any of these stocks that Fisher sold. While I agree with Fisher's decision to sell Diamond Foods and Las Vegas Sands, I'm not so sure about Celgene and Whole Foods. As a patient and long-term investor, I think these two companies still hold a great deal of promise in their respective and highly profitable yet competitive health-care and organic-foods markets.