I'm a federal retiree with a TSP account. The F fund is an index fund based on the Bloomberg Barclays Aggregate Bond Index. IIRC, the duration is around 4.5. The 8.65 1 year return reflects capital gains from falling interest rates, similar to the gains recorded by core bond funds/intermediate bond funds.

+1
FedSmith is an advertising-based publication directed at Federal employees and retirees from what I can make out. It reminds me a bit of the publications sent free of charge to me from organizations like AARP and NEA / MEA (related due to prior employment). I’d be loath to criticize the content of any of these. They mean well. But neither do they provide the depth of financial insight / information you’d find on this board generally, or at any mainstream financial information service like WSJ, Bloomberg, Barron’s, etc. That may be because FedSmith (and the ones I cited above) are aimed at a broader, less financially astute population.
Excellent point about the declining interest rate trend we’ve grown accustomed to. If you’re under 50 you may not even remember previous decades of generally rising interest rates (assuming you can only remember such things back to when you were 20). Some of us who lived through and were investing during the 70s and 80s can assure you that what you’ve lived through is somewhat of an aberration as interest rates go. Rates can and do go in either direction - rising or falling. Someone here recently mentioned paying a 12 or 14% rate on a mortgage for a first time home.
The fund referenced in the article sounds a lot like the T Rowe Price U S Bond Enhanced Index Fund (PBDIX) which I happen to own. As bond funds go, its fairly “safe” holding all / mostly investment grade bonds having short-intermediate maturities. But in a serious ramp-up of interest rates it would certainly lose money,

I'm a federal retiree with a TSP account. The F fund is an index fund based on the Bloomberg Barclays Aggregate Bond Index. IIRC, the duration is around 4.5. The 8.65 1 year return reflects capital gains from falling interest rates, similar to the gains recorded by core bond funds/intermediate bond funds.

American Funds’ Quiet Rise to Bond Dominance
https://www.barrons.com/articles/american-funds-quiet-rise-to-bond-dominance-51593714454
Incognito
https://www.google.com/search?q=American+Funds’+Quiet+Rise+to+Bond+Dominance&oq=American+Funds’+Quiet+Rise+to+Bond+Dominance&aqs=chrome..69i57j69i60l2.1043j0j7&sourceid=chrome-mobile&ie=UTF-8
While most investors have been laser-focused on stocks this year, the relative steadiness of the bond market has gone largely ignored. American Funds’ bond portfolios, however, have produced a remarkable amount of good news. Managed by Capital Group, they turned in top-notch performance during the coronavirus rout, and have steadily climbed to the pinnacle of their categories over longer periods.
The gains reflect a quiet overhaul that has transformed Capital Group, founded in 1931, into a bond giant.

Using Portfolio Visualizer I noticed that VTI had negative rolling averages in 1,3,5,& 10 time frames dating back to 1993. That might be a little too volatile for a retiree and could pose a sequence of return risk if one had to pull money from VTI during one of these lows.

@johnN
That would be 4.04% per year (compounding continuously) in the growth of the share price. Consistent with Derf's note.
Are there also dividends which would figure into your total return?
So the recent 8.65% is a big improvement over historical performance; what are they doing better now?
David

Having reached 10% allocation in both BIAWX & VWIAX, I am starting a new pair - VLAAX (50-70% Allocation) & PHSKX (mid cap growth) - using funds from VMVFX sale & selling now USMV for the same reason.

https://www.fedsmith.com/2020/07/01/which-tsp-fund-up-8-65-12-months/
Which TSP Fund Up 8.65% in 12 Months?
For those who casually watch the rate of return for the funds in the Thrift Savings Plan (TSP), this may be a surprise.
F Fund Has Best Return Over 12 Months

“It's just I'm surprised that I rarely see it used as an asset class in asset allocation, multi-sector, or unconstrained funds. It seems that they would add value & diversification”
I don’t know if this answer satisfies - but a good house with its own highly competent credit research department can do a lot better playing in the corporate bond sector than it can with Treasuries. But msf induced me to look at a couple multi-asset funds.
Here’s what Price’s Spectrum Income fund (RPSIX) does. Its latest bond holdings (from Yahoo) show 0% in U.S. government bonds, 33% in (other) AAA and an average duration of about 5 years. Since the fund typically invests 15% (more or less) in an equity fund, the percent allocated to AAA is lower than might appear at first glance. https://finance.yahoo.com/quote/RPSIX/holdings/
TRRIX is one of Price’s conservative balanced funds. Normally it targets a 60% bond, 40% equity mix. According to Yahoo the fund is currently underweight bonds by 8% at 52% of portfolio. Like RPSIX, the fund holds 0% U.S. government bonds. And, like RPSIX, they’re holding the duration to just over 5 years. The fund hews to a higher credit quality than RPSIX - with 59% of bonds rated AAA. https://finance.yahoo.com/quote/TRRIX/holdings/ ..... T. Rowe is right a lot more often than they’re wrong on the long term outlook. Problem is most of us consider 6 months long term, while they’re looking out several years. Patience pays off.
Just a personal perspective (not applicable to others): I view bond funds as a “speed-brake“ that should reduce volatility during deep stock market downturns. Earning the paltry income available today doesn’t interest me. After one of my sources, Bill Fleckenstein, cautioned his readers to avoid lower credit grades last March, I’ve strived to stay with mostly intermediate-term bond funds that invest primarily in higher credit quality. AAA, AA A, BBB all fall within that zone. Yahoo is a great spot for viewing a fund’s bond credit quality / duration / maturity. I should add that Bill made that call a couple weeks before the Fed announced their intent to buy corporate bonds. So I don’t know if the advice still stands. Suspect so.

“Though the bottom line is, I don't think I could put 70% of my total portfolio in long-term treasuries and then just forget about it.” +1
Don’t confuse / conflate long-term Treasuries with long-term Treasury funds - or, for that matter, any type of fund investing in bonds. Two different animals. Funds respond much differently to rising / falling rates. That’s because changes rates affect fund flows. If rates fall and prices rise, more investors likely buy in, causing manager to purchase more bonds at higher prices. Prices fall? Investors flee, forcing manager to sell into a weak market at potentially lower prices. Than there’s the matter of fees and operating costs associated with funds that direct bond holders don’t face.
Your question is a good one. I’m but a casual observer of bonds. But in watching multi-asset funds of all stripes over the years, I get the impression that out beyond the 10-15 year duration, you don’t need a lot of those to significantly impact a fund’s volatility and performance. I rarely see any multi-asset fund that exceeds 10-15% in long term Treasury holdings. No doubt, there are some. In essence, a little bit of this asset delivers a big bang in a diversified portfolio. They make a great hedging tool - precisely because they tend to do better in weak equity markets and pack a disproportionate amount of punch.
Not topical - But there’s an even more potent creature called “zero coupon Treasuries”. For additional enlightenment, you might like to read up on those.

Can't find a good page on this now, but there are only two reasons I know of to hold long term treasuries.
One is immunization. If you like the current yield and there's something you're saving for many years down the road, buying a long term treasury or a few to get the right duration blend is a reasonable strategy. Similar to buying a CD for a targeted purpose.
The other is speculation. If you believe interest rates are going down, you would want to own the most interest rate sensitive, i.e. longest term, bonds. This is considered a speculative strategy - a bet on interest rates - because the difference between 10 and 30 year yields otherwise tends not to justify the additional risk.
Right now 10 years are yielding 0.69%, and 30 years are yielding 1.43%. Is it worth it to you to lock in a 1.43% return, a 3/4% difference in yield, for 30 years in order to bet on interest rates going down further?
OTOH intermediate term bonds can still have a place in a portfolio as a backup for cash in one's decumulation phase. For example, one can keep 3 years in cash or "cash like" investments, and another 4-6 years in intermediate term bonds, with the rest in longer term investments. This is effectively using a bond immunization strategy, not for a long term purpose, but for a midrange one.

July 3rd Episode:

Hi @Derf, Thanks for your question. Yes, as the market continued to decline each buy step was greater than the previous with dollars invested. Why, you might ask? Time for a geometry lesson. Picture a pyramid. From the top the deeper one goes towards the base the greater the base area becomes. The same applies to the step buy approach in a falling stock market swoon. The deeper the pull back the greater the rebound opportunity. When a pull back begins one does not know how deep it will go; but, to make the better money each buy step has to become greater as the pull back goes deeper. Generally, I plan for six to eight buy steps with the first one coming somewhere after at least a five percent dip has taken place. And, as the pull back deepens there becomes less risk with each buy step that is made according to the metrics of my market barometer. Thus, for me, this warrants a larger amount being invested into each buy step based upon the reduced risk theory. This has now become a geometric buying approach. I take my pool of money that I am willing to put to work and I plan out how much I'm willing to put to work at each planned buy step Then as the market declines every eight percentage points of separation (or thereabouts sometimes I may use five or six percentage points on the buy step separations) in the downdraft I put money to work. When the market bottoms and turns back upwards I have buy steps planned as well during the updraft until I have reached my average buy in percentage. At this point I stop buying, perhaps before then if I have exhausted my pool of money.
Although, this is not the only investment strategy that is found in my tool kit it is generally how I play market declines. This is one of the reasons that I carry a sizeable cash allocation within my overall asset allocation. My baseline asset allocation that I operate from is 20% cash, 40% income and 40% equity. Currently, I am positioned at about 10% cash, 45% income and 45% equity and will adjust accordingly as I feel warranted.
As noted above in my above post(s) I'm now seeing some fixed income investments starting to look attractive when compared to the earnings yield of stocks. In addition, one may want to compare the stock earnings yield to the five year total return of these funds as well. In doing this I'm finding that the five year total return for Pimco Income (PONAX) is about 4.3% and for Lord Abbett Bond Debenture (LBNDX) it is about 4.51%.
What does all this mean? For me, it means that stock valuations have become stretched relative to their earnings. Should the stock earnings yield continue to decline then, from my perspective, my multi sector income funds become even more attractive for near term opportunity and stocks less so.

heck, VGLT and VONG 50-50 easily beat a great many things the last decade and more, not only PRWCX (VLAAX runnerup)

Thanks for catching my mix-up on dates (the portfolio visualizer can start as far back as 1985 but not this portfolio).
I typically follow EDV but that only went back to 2009 so I looked at VEDTX instead which also includes 2008.
Those other combinations are impressive.
By using WHOSX instead you can get results back to 1998 as well.
Then I looked at different percentages with WHOSX.
PV results
It looks to me that you still need a significant amount of long-term treasuries to make any real difference.
Even WHOSX/PRMTX 50/50 still beats PRWCX.
PV results
Though the bottom line is, I don't think I could put 70% of my total portfolio in long-term treasuries and then just forget about it.

Hello @Art & @Puddnhead,
Thanks for stopping by and making comment.
I should explain a little about the yield metric. Years back investors did not have all the fancy dancy ways to measure the market. One metric that my late father used was he followed the yield on the stocks he owned. When the yields got thin it was usually that the stocks he owned were at, or towards, their 52 weeks highs ... if not setting new highs. With this, he would trim the position and await a pullback where the yield would again rise as the stock price fell usually through a seasonal trend pattern.
In looking back through my data that I keep on the S&P 500 Index the recent high yield on the Index took place on (week ending) March 20th at 2.53% with a reading of 2305 and the recent low on February 21st at 1.79% with a reading of 3338. With this week's close the yield on the Index is at 1.9% with a reading of 3130. With this, and from a yield perspective, the Index is becoming pricey. In addition, TTM earnings are reported to be falling ... not rising. Based upon the blended earnings approach that the barometer uses puts the P/E Ratio for the Index at around 24. With this, This the earnings yield computes to about 4.16%. In comparing the 4.16% earnings yield to the yield of some of my multi sector bond funds ... Well, the advantage is now with some of the multi sector income funds from this yield perspective. Take the widely held PONAX (Pimco Income) is producing an income yield of 5.67%. With this, the yield advantage now goes to some bond funds ... from, my perspective.
Should the Index reach a near term yield of 1.8% Old_Skeet will most likely trim his equity allocation back to it's baseline allocation of 40% equity from the current 45% equity. Not long ago, I trimmed from around 50% equity back to 45%. Remember, I bought the downdraft and when the updraft came this put me equity heavy from the upward price movement as the rebound progressed.
Take care ... and, again ... thanks for stopping by and making comment.

Playing with your choices.
If you create a (70/30) with VEDTX / PRWCX your results are almost identical to VEDTX / VTSMX (70/30)...actually slightly better results.
I noticed you can only get results back to 2008.
Using WHOSX as a replacement fund for VEDTX gets you back to 2000. Using PRMTX as a substitute for QQQ creates an interesting set of results that you'll be impressed by.
Even more impressive equal weight WHOSX / PRMTX / PRWCX.
I might add PRHSX as an 4 fund portfolio...maybe even PRNHX as a 5 fund portfolio.
Thanks for the thread @zenbrew.

Skeeter,
As I sold all funds to cash in February before I retired I was in all cash when the pandemic started. Moved monies to Schwab and have been slowly adding funds. Bought EGFFX, RPHYX, CPOAX, JENSX, PTIAX, SWAGX, GGSOX for a start. Still have 65% in cash for now.
Art

Why aren't long-term treasuries utilized more (or actually at all) in actively managed multi-sector, unconstrained, or flexible income funds? I understand the volatility of such funds but it seems that they do add value. I got to thinking about this again after looking at the prospectus for TMSRX. I believe that they would characterize this under "Style Premia" strategy which includes currency bets (as of 4/20/20 they had 1.4% total in US treasuries).
Portfolio Visualizer for:
1) VEDTX & VTSMX (70/30)
2) VEDTX & QQQ (70/30)
3) PRWCX (100)
Dating back to 1985 (admittedly a period of decreasing interest rates):
Portfolio Visualizer results
Maximum drawdown 1 yr for:
1) -17.05
2) -9.25
3) -27.17
Final balance for a $10,000 investment would be:
1) $37,914
2) $48,708
3) $29,711
I've been following such a strategy for quite some time but never had the nerve to actually invest as such. PRWCX is my largest holding & have been very satisfied.

NYT: Deutsche Bank May Offer Wirecard a Lifeline
https://www.nytimes.com/2020/07/02/business/wirecard-deutsche-bank.html
Once again, Deutsche Bank puts on its not-so-white hat to cut a deal with a debt-ridden, likely fraudulent company that was headed by a questionable CEO. (Wirecard's former CEO is currently under arrest.)
"It did not provide any further details."

Hi guys: With the 4% gain the S&P 500 Index had this week moving from 3009 to 3130 Old_Skeet's stock market barometer scores the Index (near term) as extremely overbought with a reading of 125. I have the Index off it's 52 week high by 7.5% and up off it's 52 week low by 39.9%. All of my buy steps that I made during the recent stock market swoon are all now positive with the package as a whole returning about 32%.
My late father use to say when the yield gets thin it's time to trim. Currently, I'm finding that the yield on the Index (currently 1.9%) is as low as it has been since 2-21-20 (weekly close) when it was at 1.79% with a reading of 3338. For me, I have already been there and done that.
I wish all ... "Good Investing."
Enjoy your 4th of July Holiday!
Old_Skeet