SemGroup Corporation and Rose Rock Midstream, L.P. Announce Timing of Fourth Quarter 2012 Earnings Conference Call and Webcast

SemGroup Corporation and Rose Rock Midstream, L.P. Announce Timing of Fourth
Quarter 2012 Earnings Conference Call and Webcast

TULSA, Okla., Jan. 14, 2013 (GLOBE NEWSWIRE) -- SemGroup^® Corporation
(NYSE:SEMG) and Rose Rock Midstream, L.P. (NYSE:RRMS) today announced plans to
release fourth quarter 2012 results after market closes on Thursday, February
28, 2013.

Rose Rock Midstream,
L.P.

A joint conference call for investors will be held at 11 AM Eastern on Friday,
March 1, 2013 to discuss fourth quarter results for both SemGroup and Rose
Rock Midstream. Hosting the call will be Norm Szydlowski, president and chief
executive officer, and Bob Fitzgerald, senior vice president and chief
financial officer. A presentation of the results will be posted before the
conference call on SemGroup's Investor Relations website at
ir.semgroupcorp.com and Rose Rock Midstream's Investor Relations website at
ir.rrmidstream.com.

What:  SemGroup Corporation and Rose Rock Midstream fourth quarter 2012
           earnings conference call and webcast
When:      11:00 AM Eastern, March 1, 2013
Where:     1) Phone conference call
           * U.S. callers - 877.359.3652, pass code 88748209
           * International callers - 720.545.0014, pass code
           88748209
          2) Log on to the webcast at ir.semgroupcorp.com
          3) Log on to the webcast at ir.rrmidstream.com

If you are unable to participate in the conference call or webcast, a replay
will be available on both websites for a year following the call on the
Calendar of Events-Past Events page.

About SemGroup

Based in Tulsa, OK, SemGroup® Corporation (NYSE:SEMG) is a publicly traded
midstream service company providing the energy industry the means to move
products from the wellhead to the wholesale marketplace. SemGroup provides
diversified services for end-users and consumers of crude oil, natural gas,
natural gas liquids, refined products and asphalt. Services include
purchasing, selling, processing, transporting, terminalling and storing
energy.

The SemGroup Corporation logo is available at
http://www.globenewswire.com/newsroom/prs/?pkgid=14815

About Rose Rock Midstream

Rose Rock Midstream, L.P. (NYSE:RRMS) is a growth-oriented Delaware limited
partnership formed by SemGroup® Corporation (NYSE:SEMG) to own, operate,
develop and acquire a diversified portfolio of midstream energy assets. Rose
Rock Midstream provides crude oil gathering, transportation, storage and
marketing services. Headquartered in Tulsa, OK, Rose Rock Midstream has
operations in six states with the majority of its assets strategically located
in or connected to the Cushing, Oklahoma crude oil marketing hub.

The Rose Rock Midstream logo is available
athttp://www.globenewswire.com/newsroom/prs/?pkgid=16626

SemGroup® is a registered trademark of SemGroup Corporation.

CONTACT: Investor Relations:
         Alisa Perkins
         SemGroup - 918-524-8081
         Rose Rock - 918-524-7711
         investor.relations@semgroupcorp.com
         roserockir@rrmidstream.com
        
         Media:
         Liz Barclay
         918-524-8158
         lbarclay@semgroupcorp.com
         lbarclay@rrmidstream.com

SemGroup Corporation logo
 
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