RE:tC - TGZ and EDVThe EDV/TGZ short term price behaviour is simply a technical matter.
For merger arbs, it's a obvious trade (as long as the merger completes). TGZ is currently trading @ 13.76 and the exchange ratio is 0.47. Therefore if you go long TGZ and short EDV at current prices (currently @ 29.62), a profit is guaranteed when the merger completes (0.47x29.62 = 13.92, so profit of 0.16 per TGZ share). You cover the short position when the merger completes and your TGZ shares get exchanged for EDV ones.
Illustration: buy 1m TGZ shares & short 470k EDV. Cost of long position = 13.76m but short nets you 13.92m. Instant profit of 160k. Doesn't matter what the share prices do between now & when the merger completes.
Only risk is if the merger fails to complete.
Arbs will keep adding to EDV shorts (and TGZ longs) until the EDV price falls such that it represents 2.12x TGZ's price (when there is no longer any profit in the trade).
If you want to be cute, it would make sense to sell your EDV shares and buy TGZ instead. If you reinvested your EDV proceeeds you'd end up with slightly more EDV shares when the merger completes. Not worth the effort/risk for me, but larger holders might also do that trade.