Stocks kicked off 2013 with spectacular gains in heavier volume Wednesday, a bullish expression of investor relief over a compromise between Democrats and Republicans to dodge the fiscal cliff. IBD's new highs list ballooned and scores of leading stocks marched to big gains in hefty volume. In the IBD 50 alone, nearly two out of every five stocks marked a 52-week or all-time high. ( See the New Highs column on B1 for more color.) The Nasdaq