US STOCKS-S&P 500, Nasdaq set for 6th straight quarter of gains
* S&P 500, Nasdaq to add to string of quarterly gains
* BNY Mellon stock rises after Trian discloses stake
* MannKind rallies on FDA's approval of inhaled insulin
* Dow down 0.1 percent; S&P 500 flat; Nasdaq up 0.3 percent (Updates with GM shares; updates prices)
By Angela Moon
NEW YORK, June 30 (Reuters) - U.S. stocks barely moved on Monday after a set of mixed economic data, but the S&P 500 and Nasdaq Composite indexes were set to close a sixth straight quarter of gains, a streak not seen in more than 14 years.
Following the S&P 500's 30 percent gain last year, many investors had expected a halt to an equity bull market that is now in its fifth year.
Utilities represented the S&P 500's best-performing sector in the second quarter of the year, while the retail sector was among the weakest.
The S&P 500 has scored 22 record closing highs so far this year, which has increased concerns among some investors that the market might be due for a technical pullback. Yet the CBOE Volatility Index, Wall Street's fear gauge, has held near multi-year lows. Continuación...