Welcome to HollyFrontier's First Quarter 2018 Conference Call and Webcast. Hosting the call today from HollyFrontier is George Damiris, President and Chief Executive Officer. He is joined by Rich Voliva, Executive Vice President and Chief Financial Officer; Jim Stump, Senior Vice President of Refinery Operations; and Tom Creery, President, Refining & Marketing. At this time, all participants have been placed in a listen-only mode and the floor will be opened for your questions following the presentation. (Operator Instructions) Please note that this conference is being recorded.
It is now my pleasure to turn the floor over to Jared Harding, Investor Relations. Jared, you may begin.
Thank you, Luke. Good morning, everyone, and welcome to HollyFrontier's first quarter 2018 earnings call. I am Jared Harding with Investor Relations for HollyFrontier. This morning we issued a press release announcing results for the quarter ending March 31st, 2018. If you'd like a copy of the press release, you may find one on our website at hollyfrontier.com. Before we proceed with prepared remarks, please note the Safe Harbor disclosure statement in today's press release.
In summary, it says statements made regarding management expectations, judgments or predictions are forward-looking statements. These statements are intended to be covered under the Safe Harbor provisions of Federal Securities Laws. There're many factors that could cause results to differ from expectations, including those noted in our SEC filings. Today's statements are not guarantees of future outcomes. The call also may include discussion of non-GAAP measures and please see the press release for reconciliation to GAAP financial measures. Also, please note that information presented on today's call speaks only as of today, May 2nd, 2018. Any time-sensitive information provided may no longer be accurate at the time of any webcast replay or reading of the transcript.
And with that, I'll turn the call over to George.
George J. Damiris
Thanks, Jared. Good morning, everyone. Today, we reported first quarter net income attributable to HollyFrontier shareholders of $268 million or $1.50 per diluted share. Certain items detailed in our earnings release increased net income by $131 million on an after-tax basis. Excluding these items, net income was $137 million or $0.77 per diluted share versus a net loss of $33 million or $0.19 per diluted share for the same period in 2017.
Adjusted EBITDA for the period was $316 million, an increase of $230 million, compared to the first quarter of last year. This increase was principally driven by our Refining & Marketing segment, where we were able to capitalize on favorable crude differentials and strong product crack spreads in our markets. Our Lubricants and Specialty Products business reported EBITDA of $41 million, driven by strong rack forward sales volumes and margins.
Rack forward posted adjusted EBITDA of $56 million, representing a 14% EBITDA margin and had operating cost of $36 million. HollyFrontier continues to expect rack forward EBITDA of $180 million to $200 million for 2018 with an EBITDA margin of 10% to 15% of sales. Lower base oil cracks combined with the lumbering