13G Filing: Picton Mahoney Asset Management and Dominion Diamond Corp (NYSE:DDC)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act
of 1934

(Amendment No. 1)*

DOMINION DIAMOND CORPORATION

(Name of Issuer)

Common Stock

(Title of Class of Securities)

257287102

(CUSIP Number)

DECEMBER 31, 2015

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate
the rule pursuant to which this Schedule is filed:

	☒	Rule 13d-1(b)
	☐	Rule 13d-1(c)
	☐	Rule 13d-1(d)

* The remainder
of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class
of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover
page.

The information required in the remainder
of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of
1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions
of the Act (however, see the Notes).