Taxation of muni bonds is not so straightforward.
Thumbnail sketch:
- "gain" (actually accretion) due to OID is reportable annually as tax exempt interest (can affect SS, IRMAA)
- "gain" due to market discount is taxable as ordinary taxable income (unless de minimus, which is reported as cap gain); may be reported annually or upon bond redemption/sale
- "loss" is reported as amortized bond premium (ABP), essentially return of capital, on a yearly basis (see Form 1040-INT box 13). Cost basis is reduced accordingly.
- any additional loss is reported as capital loss at time of sale.
Simple examples:
$1K par bond is purchased for $900 (no OID), redeemed at maturity five years later for $1K. The $100 "gain" is reported as ordinary income.
$1K noncallable par bond is purchased for $1100, redeemed at maturity five years later for $1K. Each year, the tax-free interest is reduced by some amount (ABP) according to formula, which over five years totals $100. There is no loss; the adjusted purchase price is $1K.
The best pages I've found on muni bond taxation are at InvestingInBonds.com.
See http://investinginbonds.com/learnmore.asp?catid=8&subcatid=60
See also: https://scs.fidelity.com/webxpress/help/topics/learn_tax_info_year_to_date.shtml
The fun really begins when multiple considerations are combined. You can purchase an OID bond at a premium to its discounted price, called acquisition premium. In that case you have to net the OID accretion and the premium amortization.

(link)
Quotes below

-High-yield municipal bonds typically offer higher yields than investment-grade munis, but carry additional risk.
-A small allocation to high-yield munis can make sense for more aggressive muni investors—but today’s yields are low relative to alternatives.
-If you choose to venture into this part of the market, we suggest you do so via an exchange-traded fund (ETF), mutual fund or separately managed account, to help with diversification and ongoing credit monitoring.
-High-yield munis yield more than high-yield corporate bonds only for investors in the top tax brackets
-High-yield munis have historically offered returns similar to high-yield corporate bonds, but with less volatility
-High-yield munis don’t provide the same level of diversification benefits as investment-grade munis
End quotes
============================
My Comments based on the above:
As the article said, HY Munis performance is similar to HY corp with lower volatility and why I rarely own a dedicated HY corp fund.
I don’t agree with point 6.  I would replace the word diversification with ballast. HY Muni have more risk but also more diversification and sometimes lower volatility than IG Munis because HY react better to rates changes. Most times HY Munis is a pretty good ballast category unless markets are really bad like 2008. 
As a retiree with taxable accounts, I invest a big % in HY Munis and since early 2018 I even use it in my IRA because its performance is very good with lower volatility. 
An important point is that only high-income earners are really benefitting from the tax break and why I don't like it when a typical investor is looking for lower distribution funds and lose on performance.  If a bonds fund performance is 6% annually with 4% distribution while another bond performance is 4% annually with only 2% distribution, the first fund is still better after-tax.
In the last several weeks HY Munis is the biggest category I own and more than 50% of my portfolio, this is by no mean a recommendation but based on my own goals.

https://www.forbes.com/sites/martinsosnoff/2020/01/22/how-to-maintain-and-compound-inherited-wealth/#3f98161f2f58
How To Maintain And Compound Inherited Wealth
First, a brief history of financial markets:
Stocks beat bonds over a 25- to 50-year time span.
Volatility of fixed income investments can equal that of equities in both directions.
The market (S&P 500 Index) can sell at book value, now at two times book. Bond yields can range from 1% to even 15% when inflation rages.
Thirty-year Treasuries, currently yield 2%, but in 1982 during FRB tightening hit 15%. Five-year paper, a comparable trajectory.
Inflation, now at 2%, rose to 8%, early eighties. It made our country uncompetitive, as in General Motors.
Dollar depreciation or appreciation can range between minus 25% to plus 25%.
Deep-seated financial risk lurks in almost every type of asset. Banks capitalized at $200 billion can self-destruct with hidden bad loans. American International Group needed a government package of $180 billion to remain solvent after guaranteeing sub-prime loans.
Municipalities, even countries, in turn can bankrupt themselves. Consider Greece and Venezuela. Brazil, Iceland and Thailand were world destabilizing forces through their overleveraged banks even though their GDPs were miniscule. Chicago, Detroit, Sacramento, possibly New Jersey currently and New York City some 20 years ago saw the wolf at their door.
Puerto Rico now hovers near basket case status, even shamelessly falsifying their hurricane mortality numbers.

https://www.fool.com/retirement/2020/01/22/the-top-12-401k-mistakes-to-avoid.aspx
The Top 12 401(k) Mistakes to Avoid
An employer-sponsored 401(k) account can be a wonderful thing, helping you amass hundreds of thousands of dollars for retirement. Don't make any of these mistakes, though, or they could cost you -- a lot.
Most people can't sock away $26,000 each year, but the table below shows how much you might amass over time investing various sums regularly and earning an average annual return of 8%:
Years of 8% Annual Growth
Balance if Investing $10,000/Year
Balance if Investing $15,000/Year
Balance if Investing $20,000/Year
5 years
$63,359
$95,039
$126,718
10 years
$156,455
$234,683
$312,910
15 years
$293,243
$439,865
$586,486
20 years
$494,229
$741,344
$988,458
25 years
$789,544
$1,184,316
$1,579,088
30 years
$1,223,459
$1,835,189
$2,446,918
401(k) mistakes that can cost you a lot
It's clear that you'll need to be diligent if you want to build wealth with your 401(k) account. You'll also want to avoid common pitfalls. Here are 12 common 401(k) mistakes that could cost you a lot, followed by a closer look at each:
Not participating in your 401(k) plan
Not contributing enough to your 401(k)
Not increasing your 401(k) contributions regularly
Not contributing enough to get the full employer 401(k) match
Loading up on too much company stock
Staying with your 401(k) plan's default investment choices
Picking the wrong mutual funds and investments
Ignoring fees in your 401(k)
Not considering the Roth 401(k)
Ignoring important 401(k) rules
Cashing out or borrowing from your 401(k)
Not appreciating the downsides of 401(k)s

@catch, you think the article is good. I think it's average. I have read so many generic articles with generic ideas. I like to discuss specifics and help people with uniques problems because most have unique situations. I made comments about each rule and what can be improved.
As I said before, the most important rule is for someone is to start early and invest 10-15% for many years and pay all the bills monthly on time and don't touch the savings.
If you like to discuss further on any rule please post about it.

None of the rules will make you wealthy. The best way for an average person it to start saving earlier and keep saving monthly thru 401K(or similar) for years. The more you save the better you will be. Basically, if you start early to meet your employer matching amount, then increase the amount by half of your raise annually to at least 15% you will be in a great shape.
#1: Put It All In One Fund-for most investors it's a good idea and why most 401K have target funds
#2: Create Your Own Yield-most average investors can use great Multisector+NonTrad bond funds for higher yield (examples: PIMIX,VCFIX,SEMMX,IOFIX,JMUTX,JMSIX). For advanced investors who don't mind the high volatility PCI,PDI

#3: Don’t Buy A Long-Term Care Policy-correct
#4: Cut Your Portfolio Management Costs-correct
#5: Pay Off Your Mortgage Rapidly-absolutely not. Do the math and decide based on the numbers. In 2012, at the lowest mortgage rates, I took home equity loan for 5 years at 1.99% interest with zero fees. We didn't need it but it was a no-brainer to know that I cam make much more than 2% in the next 5 years.
#6: Moonlight-no if you can. Select a profession that pays well
Basically, the article is average at best. It missed the most important rule of saving early and at least 10-15% for years. It failed on what bond funds to buy (not all bonds are treasuries) and CD,MM are not a good option. The rest was the easy part.

Sorry, one more piece may be worth adding. The majority of their leverage is coming from an index swap. So they're just adding exposure to a few indices, like the S&P 500 and the Nasdaq 100 on top of their disclosed holdings and that more than doubles their exposure to equities. They also have a swap as of 9/30/19 that gives them exposure to 14 stocks where the value of that exposure adds another 50% or so of their NAV to holdings they already have at much lower exposures.
One quick and simple example as of 9/30/19. The fund directly owns 8,068 shares of Mastercard, which they show as a little more than 2% of NAV, but in one of their swaps they hold 16,000 shares of Mastercard which roughly doubles their exposure without disclosing it directly and their index swaps would again indirectly increases the fund's holdings of Mastercard based on the stock's weighting in the indexes)

Forgive me if I'm repeating a piece of the puzzle that's already been stated but I think the Venture Capital Fund is leveraged a bit more than 2:1 and that's what's driving the outsized returns, that's the secret sauce. I haven't quite figured out how they managed to only lose 22 or 23% at the end of 2018 but I guess that suggests they did a good job picking stocks or they cut their leverage in between public reporting dates and we can't see that anywhere. At the end of Q3 2018 they were something like 217% long and at the end of Q4 2018 they were more like 270% long, which is probably why they recovered from the drawdown so quickly.
M* reports the portfolio exposures incorrectly because they account for the swaps the fund uses in the "other" investments but they don't account for the notional value of those swaps. M* counts the fund's asset allocation to these swaps based on the profit or loss the fund has on the swaps but the notional value is what really matters, not just the profit or loss. You can see the notional values of the swaps by looking at the fund's quarterly schedule of portfolio holdings at sec.gov/edgar.
Just my humble opinion but because of the leverage the Leland fund uses you can't really do a performance comparison with the Primecap fund, which uses no leverage, and call it apples to apples. I'm also not sure what you intended to compare, @openice, because POAGX started in 2004, not 1984 (that was Vanguard Primecap, VPMCX), POAGX has more than $10 billion of AUM, VPMCX has more like $69 billion, and I can't figure out what period of time your performance figures relate to, the roughly 9.5% for each of the 3 funds you were comparing. It doesn't seem to be the 3 years I thought you were suggesting for either POAGX or VPMCX.

@msf, Aren’t Treasury’s federal tax-exempt?

But let’s go back 20 years to early 2000, when the S&P 500 was at roughly 1500.
If you had bought then and held until now, that works out to be an average annual return of just 4%.
4% is better than zero… but it’s hardly anything to write home about.
[This return doesn’t factor in dividends, taxes, fund management fees, or inflation… but those effects all largely offset one another.]
...since 2000, the S&P 500 has returned just 4%, while a 20-year government bond would have paid you 6.9% over the same period. That’s a HUGE difference of nearly 3%.

A most slanted "analysis".
The nominal rate of return of VFINX, including dividends and management fees was about 6.2%. (A $10K investment on 1/22/2000 would have been worth $33,232.15 on 1/21/2020 according to this

M* chart.)
The article notes that the S&P 500 figures would have been lower after taxes. Mysteriously though, it doesn't likewise take note of the ordinary income taxes that would have been owed on interest paid year in, year out by long term bonds.
Sure, VFINX spins off taxable divs, and they're significant. A fact that article chose to ignore. Still, only part of VFINX's gain would have been taxed annually. In addition, starting in 2003 those divs would have been qualified, thus taxed at the lower cap gains rate. As would its appreciation have been taxed as cap gains upon sale at the end of 20 years.
Now let's talk about reinvestment risk. Had you purchased a Treasury in 2000, you would have received taxable interest of 6.9% on that principal each year. But you would not have gotten 6.9% on your reinvested interest. You would have ridden the yield curve all the way down to 2% over the next couple of decades.
Put together the taxes and the decline of rates on reinvested interest, and that 6.2% return on VFINX begins to look pretty good. And that's including the (lack of) returns through the "lost decade".

RPHYX available NTF at Vanguard RPHIX also but $100,000 minimum. $50 redemption fee in 60 days

Why would I buy SHV when MM pays the same?
Because the Fed is expanding its balance sheet stocks and bonds are doing great..
In the last 3 months (link) SHV made 0.4% but PIMIX made 2.7% and NHMAX(HY Muni) made 3% and SPY made over 10%

My thought too. Only reason I can see is 100% defensive position. But they are buying because it is their job.

Why would I buy SHV when MM pays the same?
Because the Fed is expanding its balance sheet stocks and bonds are doing great..
In the last 3 months (link) SHV made 0.4% but PIMIX made 2.7% and NHMAX(HY Muni) made 3% and SPY made over 10%

But let’s go back 20 years to early 2000, when the S&P 500 was at roughly 1500.
If you had bought then and held until now, that works out to be an average annual return of just 4%.
4% is better than zero… but it’s hardly anything to write home about.
[This return doesn’t factor in dividends, taxes, fund management fees, or inflation… but those effects all largely offset one another.]
...since 2000, the S&P 500 has returned just 4%, while a 20-year government bond would have paid you 6.9% over the same period. That’s a HUGE difference of nearly 3%.

A most slanted "analysis".
The nominal rate of return of VFINX, including dividends and management fees was about 6.2%. (A $10K investment on 1/22/2000 would have been worth $33,232.15 on 1/21/2020 according to this M* chart.)
The article notes that the S&P 500 figures would have been lower after taxes. Mysteriously though, it doesn't likewise take note of the ordinary income taxes that would have been owed on interest paid year in, year out by long term bonds.
Sure, VFINX spins off taxable divs, and they're significant. A fact that article chose to ignore. Still, only part of VFINX's gain would have been taxed annually. In addition, starting in 2003 those divs would have been qualified, thus taxed at the lower cap gains rate. As would its appreciation have been taxed as cap gains upon sale at the end of 20 years.
Now let's talk about reinvestment risk. Had you purchased a Treasury in 2000, you would have received taxable interest of 6.9% on that principal each year. But you would not have gotten 6.9% on your reinvested interest. You would have ridden the yield curve all the way down to 2% over the next couple of decades.
Put together the taxes and the decline of rates on reinvested interest, and that 6.2% return on VFINX begins to look pretty good. And that's including the (lack of) returns through the "lost decade".

https://www.capitalists.com/blog/2020/01/21/the-investment-that-destroyed-the-sp-500/
2020The investment that destroyed the S&P 500
The year was 1990, and the Soviet Union was on the verge of collapse. The Berlin Wall was still in the process of being destroyed, and East and West Germany were set to reunify later in the year.

https://seekingalpha.com/article/4318061-federal-reserve-bank-is-buying-t-bills-and-you-should-too
The Federal Reserve Bank Is Buying T-Bills And You Should Too
Jan. 21, 2020 11:45 AM ETiShares Short Treasury Bond ETF (SHV)5 Comments
Summary
Investors should heed warning from the latest Fed move and consider purchasing the iShares Short Treasury Bond ETF.
SHV offers investors a safe return on short-term cash with a 30-day yield of 1.5% and a negative beta. The SHV is a very conservative way invest short-term capital.
The Federal Reserve Bank of New York added $60.7 billion in treasury bill purchases last week within the repo market

I put more emphasis on the last 3 years. When I compare RPHIX,ZEOIX,SEMMX,DHEIX(link)
RPHIX has inferior numbers to the other 3.
DHEIX is the only one with 80+% in investment-grade rating. I can't buy DHEIX at Schwab but I can buy DHEAX with no fees.

This was good. No-nonsense, simple, straightforward, without insulting the reader. Even a beginner could grasp it--- if that beginner is the sort who's not ALLERGIC to things financial. There's a lotta that around. Thanks, @bee. As for me: I can't bear to keep things THAT simple. But I do have some proportions in mind, to aim for. I'm comfortably NEAR those round numbers I've set for myself: 35% global stocks. 65% bonds of different sorts. (Though I don't own any EM bonds anymore. I have found other, less risky bonds that deliver decent yield--- even better monthly pay-outs than EM.) Having never built a cash position, I see that my fund managers together have got me into a 9% cash position these days. And my true allocations tonight are 33% stocks and 56% bonds. With 2% "other."

Not just T. Rowe Price.

Vanguard, the largest passive-fund manager with $3.8 trillion in assets, is likely to become the largest active manager as well within a few years. Currently Vanguard boasts $1.37 trillion in active mutual fund assets, well ahead of Fidelity and only $179 billion behind American Funds, thanks to a higher growth rate on strong inflows at a time when most such funds are seeing outflows.

and

“We think it’s more appropriate to compare ‘high cost vs. low cost’ funds, instead of active vs. passive.”

It's the economics, stupid :-)
https://www.inquirer.com/business/vanguard-jack-bogle-passive-active-mutual-fund-etf-20190527.html
(FWIW, I hold actively managed funds in both houses.)

Nasty environment for many active managers. Recent experience with some formerly good fund houses leads me to think their products have suffered as money has fled their firms. Might be a vicious cycle.
Somehow T. Rowe has managed to buck the trend.
T. Rowe Price overcomes 'choppy market environment' to beat Wall Street estimates https://www.bizjournals.com/baltimore/news/2019/10/24/t-rowe-price-overcomes-choppy-market-environment.html
T. Rowe Price has a $1 trillion answer to claims stock-picking is dead (possibly a year old, but still good read) https://www.investmentnews.com/t-rowe-price-stock-picking-franklin-resources-legg-maso-175759

Hi @Graust. I'm curious if your Fidelity order for RPHYX went through. The fund still can't be purchased at Schwab. I inquired by email and got the following response today. So far, not available.

Thank you for reaching out to Charles Schwab eServices with your inquiry on RPHYX last week. While the website for RPHYX may report that this fund has been re-opened to new investors, it is not guaranteed to be made available for purchase at Schwab. That being said, the Mutual Fund Support Specialist still advised that you reach out in about a week to see if any updates have been made to the availability status of RPHYX at Schwab. You can chat in, or call our General Customer Service Line at 800-435-4000 and we will be able to research that for you.