I don't have the crystal ball of others and I haven't added any MNTA but I certainly am not selling at these prices.
To me my reasoning is like this: 1) Sandoz thinks Momenta's technology is worthy enough to partner on MULTIPLE products. This is a pretty big player in generics too! 2) MNTA's technology has now been (officially) blessed by FDA. 3) While others have talked about entering the biosimilar/biogeneric/bioequivalent/biobetter... space Momenta has a clear lead at this point. 4) Another player wanting to enter would do a lot worse off then starting with Momenta even with a nice premium. 5) I think the potential of Momenta's technology to produce new compounds like M118 & 402 offers a lot of upside potential. 6) In addition to 356 there are other compounds (and likely more in the works).