Warren Buffett's 'single best measure' of stock market value falls short in 3 big ways (BAC, BRK.B, BRK.A)
<p class="p1"><span class="s1"><img style="float:right;" src="http://static3.businessinsider.com/image/558c0cc569beddfd3c246431-1800-1350/warren-buffett-63.png" alt="warren buffett" data-mce-source="Bill Pugliano/Getty" />The Oracle of Omaha is facing some opposition.</span>
<p class="p1"><span class="s1">In a note to clients on Monday, Bank of America Merrill Lynch's Savita Subramanian wrote that Warren Buffett's favorite metric of long-term value "may have limited utility."</span>
<p class="p1"><span class="s1">The market cap to GDP ratio, which once characterized as the "single best measure" of value, is used to determine whether the stock market is overvalued or undervalued. </span>
<p class="p1"><span class="s1">And given that this measure shows the S&P 500 is 80% above its historical average level, some might find signals from the market cap to GDP ratio concerning. But BAML is skeptical about how good of a measure it actually is of the stock market's value. </span>
<p class="p1"><span class="s1">Subramanian points to three main reasons why the metric is not one of BAML's favorite for valuing equities:</span>
<ol>
<li><span style="line-height: 1.5em;">Market Cap/GDP is like Price/Sales, "with all of its shortcomings and more." BAML adds that neither measure takes structural changes in profit margins into account, which is problematic. In 2014 corporate margins grew to new highs due to lower taxes, lower interest expense, and higher operating margins in tech.</span></li>
<li><span style="line-height: 1.5em;">Global GDP should be used because it is more closely tied to the S&P 500 than US GDP. This is because S&P companies are generating more and more sales and profits from overseas, not just in the United States.</span></li>
<li><span style="line-height: 1.5em;">There are too many mix differences between the US equity market and the entire US economy. For example, sectors like technology and energy hold a much stronger weight in the stock market than they do for US GDP.</span> <span style="line-height: 1.5em;">Also, US GDP is more services-oriented, while profits from S&P companies are more goods-oriented.</span></li>
</ol>
<p class="p1"><span class="s1">Here's what the Market Cap to GDP ratio has looked like since 1964:</span>
<p class="p1"><span class="s1"><img src="http://static5.businessinsider.com/image/55ad19702acae72c008b819c-1464-551/screen-shot-2015-07-20-at-11.50.16-am.png" alt="Market Cap/GDP" data-mce-source="Bank of America Merrill Lynch" />And so this measure currently makes the stock market look expensive, but at least in BAML's view, there are plenty of reasons not to worry about something that might have the world's most famous investor concerned.</span>
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