Momenta Pharmaceuticals, Inc. (MNTA)

[DewDiligence]

MNTA Major Shareholders

[Updated for SEC filings through 2/27/09. Officer/director
holdings shown below are as of today and include all options,
whether or not they are currently exercisable. Institutional
holdings shown below are as reported on Form 13G and
are accurate as of 12/31/08.]

 
                        Shares   Stake 
 Novartis             4,708,679  11.8% 
 Visium Asset Mgmt    3,349,122   8.4% 
 T Rowe Price         3,338,081   8.4% 
 Federated Investors  2,824,546   7.1% 
 Samana Capital       2,109,760   5.3% 
 Palo Alto Investors  1,183,658   2.9% 
 Robert Langer*       1,046,022   2.6% 
 Craig Wheeler†         991,562   2.5% 
 Alan Crane‡ (Polaris)  652,602   1.6% 
 G. Venkataraman**      628,640   1.6% 
  
 *Director and co-founder. 
 †Director and CEO. 
 ‡Director and former CEO. 
 **SVP, R&D. 
  
 Atlas Venture Fund, which was a 6.7% holder as of 4/1/08, distributed its 
 shares to the limited partners and no longer holds shares in its own name.