NEW YORK ( ETF Expert) -- It may be too early to declare that the “do whatever it takes” rally is dead in the Mediterranean Sea. After all, there is still a fair amount of interest in buying broad market stock ETFs on weakness.For example, on Wednesday, block trading institutional investors snatched up shares of the iShares S&P 100 ( OEF) on 12 times the normal trading volume. The activity increased OEF’s net assets under management by an attention-grabbing 3%. By the same token, there are equally intriguing contradictions. For instance, since Mario Draghi’s July 26th pledge to do anything and everything to get the eurozone through its debt crisis, the percentage of S&P 100 stocks above a long-term moving average had collectively remained above a 200-day trendline; that is, they were able to hang in there until Tuesday. In fact, with more selling taking place on Wednesday, one can expect the slide to be even more pronounced. It is difficult to visualize an October surprise where buyers completely throw in the towel on Apple ( AAPL) or the broader U.S. market. The large-scale block purchases of OEF demonstrate that selloffs on global growth concerns are not new; they also demonstrate the strength of the world’s central banks to act as a backstop. On the other foot, forward-looking earnings estimates in a stagnant economy are likely to decline and disappoint. It follows that plenty of money managers are going to look for a margin of safety. They’ll focus on corporations with increasing revenue prospects (a la price-to-sales), rather than hitch a ride on an earnings express (a la price-to-earnings). What might this mean for ETF enthusiasts? It may mean that you can find lower volatility and greater price stability in a revenue-weighted vehicle. The one that comes to mind is the RevenueShares Large Cap Fund ( RWL). Due to the fact that RWL is ranked by revenue, not by market cap size, the top holdings represent some of the most predictable revenue stream winners around. For example, RWL’s top holding is Walmart ( WMT), which reported a 4.5% revenue increase last quarter.