I have two questions about iTraxx single tranche deal mechanics. To make my questions more accurate, let's work with some actual data.Today's on-the-run iTraxx series is S25 and let's focus on the 5Y index. This 5Y index has the effective date Mar 21, 2016 and Maturity Jun 21, 2021. Q1: If an investor enters a tranche (e.g. 3%-6%) deal of this 5Y index (S25), will the deal always mature on Jun 21, 2021 irrespective of the date the deal was entered into? I mean - the deal does not mature at "deal date + 5Y" but on Jun 21, 2021.Q2: Do I understand it correctly that if an investor enters a tranche deal (5Y S25), the names in the credit portfolio are 'fixed' for the investor and the defaults of these names only are taken into account for the future premium/protection payments? I mean if, say, Deutsche Bank is part of the index at the trade date, is removed from the iTraxx e.g. 2 years later (for being downgraded) and defaults after one more year, the tranche notional is possibly affected by this default.I have searched in the literature but I cannot find exact answers to these questions.Thanks

Your understanding is correct in both cases. S25 defines both the portfolio and the maturity date, which stay constant. You should be able to find full deal specifications on Markit's website, as well as more general documentations like their credit index primer.

Great, thanks a lot.