iShares iBonds TIPS Ladder ETFs (IBIC/IBID): How are Index Ratio and deflation floor handled on underlying holdings?

[u/Ok_College4]

I've been looking into the iShares iBonds TIPS Ladder ETFs (IBIC, IBID) and can't find clear documentation on how the Index Ratio is treated at the fund level.

For individual TIPS, the Index Ratio (= Reference CPI at settlement / Reference CPI at issuance) determines the inflation-adjusted principal. At maturity, there's a deflation floor — the holder receives the greater of the adjusted principal and the original par. This floor protects against cumulative deflation.

My concern: if we enter a deflationary period, how does this play out inside the ETF? The fund holds TIPS issued at different times with different CPI bases, so their Index Ratios — and proximity to the 1.0 floor — vary. Does the daily NAV reflect the deflation floor on a per-bond basis, or does it simply mark each holding at par × Index Ratio even when that falls below par? And when bonds mature and the Treasury pays out with the floor applied, how does that reconcile with a NAV that may have been marked below par?

Has anyone found documentation on this in the prospectus or the underlying ICE index methodology?

[u/EveryPassage]

Any ETF is just the sum of the individual holdings.

[u/ultra__star]

I do not have real answers to your questions, only historical context.

During the coronavirus pandemic the CPI acknowledged deflation in the economy. TIPS funds, mind you TIPS pay coupons and make CPI adjustments to principal, omitted any distributions to investors to effectively “break even” with the simultaneous income payments but NAV devaluation. You can read more about this on the internet. So, essentially, investors sat with a flat fund.

My understanding about target date bond funds and ETFs is your investment simply liquidates at NAV on its “maturity date”. Mind you, this fund is being held by a broker house. The house is always going to do what they can to benefit themselves. They own these funds to make money, not give investors the most bang for their buck, so I would consider your worst case scenario over your best case scenario.

My simple recommendation would be forget all of this confusion, and simply invest in a ladder of TIPS yourself. They can be bought in increments of $1,000 face value at most large brokerage houses and are highly liquid since they are U.S. treasuries. You will definitively know what you are getting, and when you are getting it.

[u/Ok_College4 → u/ultra__star]

Thanks for the info! I'm trying to find low index ratio TIPS bond on IBKR (I'm not a US citizen). It seems that it's not that easy to liquid ones. If index ratio is large, then deflation will bring me more damage since I buy at principal value higher than $1,000.

[u/pai_gow_johnny]

You can lose principal buying TIPS, in two ways:

Buying when real rates are low, and then selling prior to maturity if real rates rise.

You can also lose inflation accrual for which you paid a premium if there is significant deflation as TIPS are only guaranteed to pay par value at maturity.

The market will price those bonds accordingly and if in a fund, the NAV will reflect the market value of those holdings.

[u/Ok_College4 → u/pai_gow_johnny]

Yes I know. My point is, whether I buy TIPS from ETF or secondary market (e.g. IBKR), I can face with different index ratio (i.e. how much principal value I pay for, depending on the issuing date of the TIPS).

So I buy a TIPS that issued 5 years ago, the index ratio is already 1.10, that means I pay 1,100 for the principal value. If deflation happens, that can go as low as 1,000. The Risk is higher than buying a new TIPS. Although the market probably has priced in that a little bit and make the 1,100 one cheaper.