The Dow Jones Industrial Average enjoyed its best gains of May as crude oil enjoyed an unexpected surge above $44 a barrel. Crude had seen erratic swings in recent days as a global supply glut continued unabated. Allergan (AGN - Get Report) rose after announcing a new $10 billion stock repurchase program. The drugmaker intends to repurchase as much as $5 billion in stock in the next six months. Shares also got a boost after first-quarter earnings beat estimates. Lumber Liquidators (LL - Get Report) was under pressure as it continued to face the fallout from a product safety scandal last year. Dean Foods (DF - Get Report) swung to a first-quarter profit as lower raw milk prices boosted margins. TheStreet's Keris Lahif reports from Wall Street.