The Nasdaq Composite fell 0.2% in midday trading, but a quick glance at market internals would suggest the index would be rallying. The number of stocks gaining ground on the Nasdaq exchange outnumbered decliners 1,726 to 1,118, while volume in advancing stocks represented 57.8% of total volume. Keep in mind the Nasdaq Composite is market-capitalization weighted, and shares of the three most valuable companies by market cap are all losing ground. Microsoft Corp.’s market cap is $1.05 trillion and the stock is down 0.1%; Apple Inc.’s market cap is $981.4 billion with the stock shedding 2.7%; and Amazon.com Inc. shares are down 0.3% to lower the market cap to $909.1 billion.Market Pulse Stories are Rapid-fire, short news bursts on stocks and markets as they move. Visit MarketWatch.com for more information on this news.