I think of silos in conjunction with differing parts of a containing portfolio. I don't think this is necessarily correct, nor is it important, but as I read your response I felt that the silos I was referring to were more defined by when they are tapped, and in what order, and hence how they are positioned (strategy), rather than separate sources contributing to a combined income stream.
The separate sources in this case I think of as tranches.
You know, I'll bet we could just flip-flop the terms and they'd be equally appropriate, so long as there's sufficient context differentiate between them.
2007 -2009, we all got caught in the Great Recession. (57/60)
Determined to have a retirement that is dotted line connection to Markets and US Economy.
Recommend, tl:dr
Devised a silo $ farm: retirement that is flexible and could standup well to shocks any of the silos. IF the "Big One" hits, everyone's retirement would affected but some more than others.
Silos:
-SS (2);
-Pension(1);
-House (1);
-Farmland(1) non divisible; Later sold to buy 2 rentals. Now 1 rental.
-IRAs, (many) that were in "tranches" or individually silo'd into deferred, longevity, variable GWLB annuities, and later in fixed GWLB Annuities). (7)
-Roths in GLWB annuities( 2) and later closed when their guaranteed 5% step-ups ended. And used to buy a downside home condo, Eastside Seattle area. Sale of Oregon home only covered a little more than half of Seattle's purchase.
-non retirement fund in GLWB annuity.
-managed IRA fund account.
-trading accounts.
2022, saw only the managed account and trading accounts materially affected by the interest rate resets. But they are silo'd as non-essential. Income from the other Silo'd vehicles are unaffected for Retirement Income.
2023, the plan is to take the AWD (Allowable Withdrawal Distributions) from the annuities without affecting the Income Annuitization Base. Previously we were only taking RMD's and not the AWDs.
So most people arrange their retirement based upon their Portfolio value. Where as they should be basing their retirement on How their assets give them Income and for long enough time. RMD is designed to extinguish your Portfolio and thus your Income. So retirees devised all types of portfolios to minimize RMD and effects of SWR.
NOTE: Tried to replicate O-PERS. GLWB Annuities have changed substantially since 2008-2018. There's a hefty fee in buying this type annuity but the annuity company has taken on Longevity, Market and Interest rate risk. If we live longer than the cash value of the annuity (~87) we will be paying taxes on zero $ cash balance. Mom lived to 97. Dad 99. Wife's parents 97, 90. Aunt to 107. Another aunt to 92 with the last 3 years essentially brain dead but breathing and strong heart.