"The Goldilocks era of post-crisis M&A has never been an if, but a when," says JPMorgan (JPM) vice-chair James Lee. "CEOs are declaring that day has come." Including the Berkshire buy, $40B in deals were announced yesterday and $140B this month. Transaction volume is up 27% Y/Y vs. an 8% slump for 2012. It should mean sweet profits for the newly lean banks.