13D Filing: Harvest Fund Advisors LLC and Semgroup Corp (SEMG)

Item 5(c) of the Schedule 13D is hereby amended and restated as follows:

(c) Except as set forth in Schedule 1 of this Amendment No. 1, none of the Reporting Persons has effected any transaction in Common Stock
since those reported on the Original Schedule 13D filed by the Reporting Persons on October 26, 2017.

Item 6. Contracts, Arrangements,
Understandings or Relationships With Respect to Securities of the Issuer.

Item 6 of the Schedule 13D is hereby amended and restated as
follows:

As of November 1, 2017, an indirect subsidiary of The Blackstone Group L.P. has entered into notional principal amount
derivative agreements (the Derivative Agreements) in the form of cash settled swaps with respect to 20,686 shares of Common Stock (representing economic exposure to less than 0.1% of the Common Stock). The Derivative Agreements
provide such holder with economic results that are comparable to the economic results of ownership but do not provide it with the power to vote or direct the voting or dispose of or direct the disposition of the shares of Common Stock that are the
subject of the Derivative Agreements (such shares, the Subject Shares). The Reporting Persons disclaim beneficial ownership in the Subject Shares. The counterparties to the Derivative Agreements are unaffiliated third party
financial institutions.