The 15% year-to-date rally in the S&P 500 (.SPX) is pulling once doubtful investors back into the market. Meanwhile, options investors are buying calls - bets on upside in stocks - at levels not seen in years. A record 1.8 million S&P 500 calls traded on Thursday, helping lift the one-month moving average of calls-to-puts to the highest in at least four years, Trade Alert data showed. The S&P 500 has posted a median gain of 18% in the 12 months after clearing the 20% threshold, LPL Financial data showed. One encouraging signal is that a greater number of S&P 500 stocks are heading higher, in addition to the handful of megacap growth names such as Microsoft (MSFT.O) and Nvidia (NVDA.O) that led gains this year.

---

Persons: you've, Emily Roland, Goldman Sachs, Willie Delwiche, we're, Delwiche, Brent Kochuba, Matt Stucky, Ken Mahoney, Lewis Krauskopf, Saqib Iqbal Ahmed, David Randall, Ira Iosebashvili, Richard Chang Organizations: YORK, National Association of Active Investment, Bank of America, Deutsche Bank, Trade, John Hancock Asset Management, Mount Research, American Association of, Investors, Northwestern Mutual Wealth Management Company, Fed, Microsoft, Nvidia, Asset Management, Thomson Locations: U.S