Very well said @SIbsj0t.
Everyone is assuming the absolute worst. Well SSnC would not have bought DST if it was not such a great company WITH talented, experienced employees. Try to be optimistic about this merger. Yes, there will be some layoffs here and there. There will be growing pains as the new company grows the business and EXPANDS. Yes expands. Try to see the positive, there will be GROWTH, which means JOBS. And yes there will be many people who are promoted into new roles and many who will remain in the position they accepted when they started DST.
Have faith that everything will be okay. and if you do get laid off, they economy is doing very well so you should have no problem getting another job.