Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The Dow Jones Industrial Average (DJINDICES:^DJI) is up as markets continue their relentless surge forward. The DJIA is being pulled up by the financial sector, as Federal Reserve chair-designate Janet Yellen's confirmation hearing yesterday reinforced investors' views that the Fed's stimulus policies will continue. However, ExxonMobil (NYSE:XOM) is the Dow's leader today after it was reported that Warren Buffett had taken a $3.5 billion stake in the oil major.

As of 1:33 p.m. EST the Dow was up 44 points to 15,920. The S&P 500 (SNPINDEX:^GSPC) was up two points to 1,793.

Speaking yesterday before the Senate Banking Committee, Yellen said she wants to see a self-sustaining recovery before the Federal Reserve eases up its stimulus efforts. She noted: "A strong recovery will ultimately enable the Fed to reduce its monetary accommodation and reliance on unconventional policy tools such as asset purchases. I believe that supporting the recovery today is the surest path to returning to a more normal approach to monetary policy." All signs indicate that Yellen will continue the policies of current Chairman Ben Bernanke, meaning a zero-interest-rate policy and continued large-scale asset purchases.

Yellen suggested an addition to the Federal Reserve's dual mandate of full employment and low and stable inflation: "a safe and sound financial system." Regulators around the world have pursued this by increasing capital requirements for banks, as well as requiring yearly stress tests. However, the problem of too-big-too-fail banks still persists, and it is unclear what unintended effects are being created by the Fed's continued stimulus and rising balance sheet, now at $4 trillion. As the U.S. financial system grows further centralized around the Fed, the risk of a shock to the system doing real damage increases.

While many investors are sitting on the sidelines, there was news today that Warren Buffett has bought a 40 million-share stake in ExxonMobil. This is Berkshire's largest outright purchase since it invested $10 billion in IBM in 2011. While that's a big investment, Berkshire's total portfolio is worth roughly $100 billion, so this is a just a 3% position within those holdings.