The WSJ reprots that Berkshire Hathaway (BRKA) has acquired a small stake in Kraft Foods (KFT), joining veteran Wall Street raiders Carl Icahn and Nelson Peltz as investors in the co. The Berkshire stake, which is less than 5%, predated news of Mr. Peltz's activist position last month. It is unclear whether Mr. Buffett sides with the activists or with the mgmt, but he has a history of betting on co’s that have strong brands and are comeback stories. “Heard on the Street” discusses American Express (AXP) , saying that the co is growing at a record pace, and that is making some investors nervous. Although most credit-card issuers would salivate to achieve the 21% loan growth that AmEx notched in the 2Q, the leap contributed to a steep selloff in its stock this week. The concern is that the co is increasing its exposure to consumers at a time when some of them may have trouble paying their bills. But many investors and analysts remain bullish on the co's prospects, saying the recent drop doesn't reflect AmEx's ability to attract the nation's most-creditworthy consumers who are putting more of their purchases on plastic. And as spending levels on AmEx cards continue to rise, they say, the co's core business of processing transactions will keep churning out strong results. "Has American Express made a massive mistake on evaluating the creditworthiness of their borrowers? I don't think that's likely," says Henry Asher, of Northstar. Barron’s Online discusses Callaway Golf (ELY) , saying that while the stock has soared to its highest levels in a decade in response to consumer demand and restructuring initiatives, it could swing lower as the peak summer season wanes amid continued concern about overall consumer discretionary spending. Discounting of golf-club prices, delayed in part by the 1-mo recall of Nike's new square-shaped driver, is also expected to tee off in the coming mo’s. In addition, Callaway is still in the midst of turning around Top-Flite Golf. Callaway execs have also made their first and largest insider stock sales in years, indicating that there may be limited upside in the near term. The stock is up 39% in the past 12 mo’s, vastly outperforming peers. The stock is trading 19.8x ests for the next 4 qrtrs. Tim Conder, of AG Edwards, says the lackluster reaction is because "2007 will create tough comparisons for 2008, and ppl are just noticing the significant amount of YTD insider selling." “Inside Scoop” section reports that while Wall St. saw the IBM (IBM) qrtrly results as a catalyst for further gains, two longtime IBM execs used the postearnings window as a chance to sell stock. SVP Linda Sanford sold nearly 75% of her IBM stake, or 12K shares. Sanford took in over $1.4m through the sale. Additionally, Steven Mills, SVP and group exec for software group, sold 20K shares for $2.3m. Mills is one of IBM's most predictive sellers, which indicate that Big Blue's shares have fallen by an avg of 5.1% in the 6 mo’s following Mills' seven prior sales. Yet, Ben Silverman, of InsiderScore.com, says the recent sales are not large enough to raise concern. "This is one of those situations where the activity is modest. It's trumped by the stock performance and the co's results," Silverman says. "And by who the co is."