(Adds analyst estimates, details on refining business)
July 30 (Reuters) - U.S. refining company Phillips 66 on Wednesday reported a lower quarterly profit that fell short of Wall Street expectations as discounts for certain crude oils shrunk and diesel profitability decreased.
The Houston company, which also has a large chemicals business, had a second-quarter profit of $863 million, or $1.51 per share, compared with $958 million or $1.53 per share in the same period a year earlier.
Earnings in Phillips refining business fell 14 percent from a year ago to $390 million as its ability to profit from producing distillates like diesel declined.
Analysts on average had expected a profit of $1.70 per share, according to Thomson Reuters I/B/E/S. Excluding items, Phillips 66 had a profit of $1.51 per share. (Reporting by Anna Driver; Editing by Franklin Paul and Meredith Mazzilli)