Hi,

I am looking for advice on buying TIPS in 401k brokerage link account at Fidelity. I am planning to have a few rungs maturing every 5 years or so, as it seems simpler than trying to fill every year.
For some of my rungs, e.g. 30 years, I have an option of buying new issue vs secondary. I've heard following pros of buying new issues:
- not paying spread (looks to be around 0.5% in price / 2% in yield for longer maturities and increases (?!) for shorter maturities)
- take away market timing
- question: does new issue auction pricing tend to be a little better than secondary market rates would tend to suggest at the same time? i.e. is there some small free lunch due to some mechanics of how this works?
Potential pros of secondary:
- Looks like buying in secondary market lets me buy maturity that is a little less at yield that is a little more: e.g. at the moment, I can buy 2045 maturity at 1.054% yield vs 2047 maturity at 1.048% yield; i.e. about 0.6% in yield difference (or ~1/3 of the spread) for slightly smaller duration.
- Of course, for some rungs, there is no "new issue" that applies.
Am I missing some others?

Please help.

I didn't find the right solution from the Internet.

References
https://www.bogleheads.org/forum/viewtopic.php?t=213815
Motion Graphics example

Thanks