Corporate America sold nearly $75 billion of stock in May. Here's what unleashed the record-setting equity resurgence — and a huge payday for Wall Street banks.

· Corporate America sold record-shattering amounts of stock in May.
· IPOs and other equity issuances were overshadowed this spring as stock markets tanked and corporates rushed to raised debt instead. 
· But volatility has faded and markets have rebounded, thanks in part to stimulus from the Federal Reserve. Stock issuance...