Suncor Energy Inc. and Canadian Oil Sands Limited are pleased to announce that they have reached an agreement to support the offer by Suncor to purchase all of the shares of COS.

Under the terms of the support agreement (the "Agreement") Suncor has agreed to amend its offer (the "Amended Offer") to provide for an increase in the original offer to COS shareholders to 0.28 of a Suncor share for each COS share. The Amended Offer, with a total aggregate transaction value of approximately $6.6 billion including COS' estimated debt of $2.4 billion, has the support of the Boards of Directors of both companies.

The COS Board has received an opinion from its financial advisor, RBC Capital Markets, that, as of January 17, 2016, the consideration under the Amended Offer is fair, from a financial point of view, to COS shareholders. The COS Board has determined that the Amended Offer is in the best interests of COS and recommends that shareholders tender to the Amended Offer.

"We are pleased to have the support of the COS Board of Directors and shareholders, including Seymour Schulich, and have been advised of their intent to tender their shares" said Steve Williams, Suncor's president and chief executive officer. "We believe this transaction delivers excellent value to COS shareholders while maintaining Suncor's commitment to capital discipline, providing both companies' shareholders with near and long-term value. Together, we're bringing this full, fair and final offer to COS shareholders and we encourage everyone to tender their shares."

"Since Suncor made its initial offer, our Board has remained steadfast in our commitment to maximize value for all shareholders. This agreement fulfills that commitment, providing our shareholders with a higher exchange ratio for their shares despite a 37 percent decline in spot oil prices," said Don Lowry, Chairman of Canadian Oil Sands. "Our shareholders clearly signaled they expected more for their COS shares, and the Board has worked to secure that under very challenging circumstances. Given the current market for energy equities, we recommend shareholders tender their shares to Suncor's improved offer."

"I am pleased that working in conjunction with the COS Board, together we have been able to improve the terms of the offer for our shares. I will be tendering my shares, and consistent with the COS Board's recommendation, I encourage my fellow shareholders to tender their shares" said Seymour Schulich, a major holder of COS shares.

A notice of variation and extension for the Amended Offer is expected to be mailed to registered security holders of COS by the end of this week and will be filed on COS' SEDAR profile. The Amended Offer will include an extension of the expiry time which is currently anticipated to be extended to 4:00 p.m. (MT) on February 5, 2016. COS shareholders are urged to carefully review this document in its entirety.

The Amended Offer is subject to certain conditions, including the acquisition by Suncor of at least 51% of the outstanding Shares (calculated on a fully-diluted basis) being validly tendered under the Amended Offer and not withdrawn. This minimum tender condition has been lowered from 66 2/3%. Suncor has agreed that if it takes up any Shares, that it will pursue a subsequent acquisition transaction to acquire any shares not tendered to the Amended Offer. As a result of lowering the minimum tender condition to 51%, there have been changes to the expected U.S. federal income tax consequences to accepting the offer and Suncor now expects that the receipt of Suncor common shares in exchange for COS common shares pursuant to the Amended Offer will be a taxable transaction for U.S. federal income tax purposes. COS shareholders are urged to carefully review the amended U.S. federal income tax disclosure to be provided in the notice of variation and extension. The Amended Offer will continue to allow a tax-deferred rollover for Canadian shareholders of COS.

The Agreement provides that COS' Board will issue a notice of change to its directors' circular that will contain its favourable recommendation to COS shareholders, together with the fairness opinion provided by RBC Capital Markets. COS expects to issue and mail the notice of change with Suncor's notice of variation and extension in connection with the Amended Offer. The Agreement contains, among other things, provisions for the suspension of dividends in the first quarter of 2016 by COS, for non-solicitation of competing offers, provided that COS has the right to consider superior proposals from other parties, subject to a right on the part of Suncor to match any such proposal and for a $130 million break fee payable by COS to Suncor in certain circumstances if the offer is not completed.

Shareholders who tender by the expiry date, assuming the Amended Offer conditions are satisfied on that date, will be entitled to receive Suncor's first quarter 2016 dividend anticipated to be paid in late March, 2016.

JP Morgan and CIBC World Markets are financial advisors to Suncor. Blake, Cassels & Graydon LLP and Sullivan & Cromwell LLP are Suncor's legal advisors. RBC Capital Markets is COS' financial advisor. COS' legal advisors are Osler, Hoskin & Harcourt LLP and Norton Rose Fulbright Canada LLP (advisor to the COS Board). COS' strategic shareholder services and communications advisor is Kingsdale Shareholder Services.

About Canadian Oil Sands Limited

Canadian Oil Sands holds (TSX:COS) a 36.74 percent interest in the Syncrude project, the largest producer of light, sweet synthetic oil from Canada’s oil sands. As a pure play in Syncrude, Canadian Oil Sands provides investors with long-life, light crude oil exposure and since 2001 has paid dividends totaling $7.9 billion.

About Suncor Energy

Suncor Energy (TSX:SU)(NYSE:SU) is Canada's leading integrated energy company. Suncor's operations include oil sands development and upgrading, conventional and offshore oil and gas production, petroleum refining, and product marketing under the Petro-Canada brand. A member of Dow Jones Sustainability indexes, FTSE4Good and CDP, Suncor is working to responsibly develop petroleum resources while also growing a renewable energy portfolio. Suncor is listed on the UN Global Compact 100 stock index and the Corporate Knights' Global 100. Suncor's common shares (symbol: SU) are listed on the Toronto and New York stock exchanges.