We all know SGEN is a great company and the leader in ADC's. IMGN is the #2 but, over the next 3-12 months there's a good chance IMGN could outperform SGEN, the price and valuation gap has grown too large. IMGN has already raised cash and is looking forward to their first approval and launch of a major blockbuster with Roche. If I were sittling on large gains in SGEN, I would consider taking the gains under the 15% tax deal, swapping into IMGN for at least the next 3 months, then cost averaging back into SGEN over the next year. A 50:50 or 75:25 position in both would seem wise. IMO, not advice, do your own DD.