I show an 8% coupon for the Mex. bonds held by my PRSNX. The character of this fund has morphed a bit, taking on more risk than before. Or maybe it's a product of being labeled differently by M* and therefore the stats are being compared now to oranges, rather than apples, so to speak.

Coupon may be quite a bit different from yield. I'm guessing that you're talking about the second largest holding in the fund's portfolio, United Mexican States, 8%, maturity 12/07/2023.
http://portfolios.morningstar.com/fund/holdings?t=PRSNX&region=usa&culture=en-US
Here's some detail on that bond (assuming I found the right one). It's trading above par, so its actual YTM is 6.77%.
https://markets.businessinsider.com/bonds/8_000-mexiko-vereinigte-staaten-bond-2023-mx0mgo000003
But it is denominated in pesos (See here for currency.) So you have to discount that yield by the anticipated loss in value of your principal between now and the time the bond matures, due to higher inflation in Mexico than one finds in the US.
In short, don't let yourself get carried away by high coupons, without checking out the premium on the bond and the expected loss on the foreign currency.
(I can say with some confidence that the currency has a lot to do with the nominal high yield, because if you use the same site to check for Mexican bonds denominated in USD, you'll see much lower YTMs.)

FYI: We study compound returns to nearly 62,000 global common stocks during the 1990 to 2018 period, documenting that the majority, 56% of US stocks and 61% of non-US stocks, under perform one-month US Treasury bills over the full sample. Focusing on aggregate shareholder wealth creation measured in US dollars, we find that the top-performing 1.3% of firms account for the $US 44.7 trillion in global stock market wealth creation from 1990 to 2018. Outside the US, less than one percent of firms account for the $US 16.0 trillion in net wealth creation. These results highlight the practical implications of the fact that the distribution of long-run stock returns is strongly positively skewed.
Regards,
Ted
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3415739

FYI: Mutual fund fees have been falling for seven years, and the trend isn’t slowing.
By 2025, combined active and passive expense ratios will decline by 22 percent, according to PwC’s 2019 U.S. Mutual Fund Outlook released Tuesday.
Managers have long measured success by the amount of assets under management. But declining fees have altered that metric.
Regards,
Ted
https://www.institutionalinvestor.com/article/b1gdcdxtq5rvh0/Fees-Are-In-Free-Fall-and-They-re-Not-Stopping

https://www.barrons.com/articles/mexican-bonds-look-tempting-but-investors-should-proceed-with-caution-51563551322
A 4% yield is tough to turn down in a world with $14 trillion in negative-yielding bonds. But be prepared to get out of Mexico fast.

@_catch22 - hi sir. just making small comparsons between chinese stocks/sp500 to brk.b that's all.
I held /bought and add intermittently since 2009, very happy w/ results so far
big fan of Mr Buffett here.
wonder what will happen to brk.a/b if he passes

5 yrs return still superior to spy or fxi
Still holding on

@Lewis You got to be kidding me, Pocahontas's, recession scare appears long on fear, short on facts.
Regards,
Ted
https://www.cnbc.com/2019/07/22/elizabeth-warrens-recession-scare-is-long-on-fear-short-on-facts.html
National Review:
https://www.nationalreview.com/2019/06/elizabeth-warren-terrible-plans/
Washington Post:
https://www.washingtonpost.com/opinions/elizabeth-warren-has-lots-of-ideas-bad-ideas/2019/06/19/ec645b36-920e-11e9-b58a-a6a9afaa0e3e_story.html?noredirect=on&utm_term=.e44670e19a1c
Mises Institute:
https://mises.org/power-market/another-reminder-elizabeth-warren-fraud
Washington Examiner:
https://www.washingtonexaminer.com/opinion/elizabeth-warren-is-wrong-this-race-really-is-about-the-size-and-scope-of-government

It looks we've got a repeat.
https://mutualfundobserver.com/discuss/discussion/51340/prospect-of-fed-cut-pushing-dividend-investors-into-tech-energy

FYI: Warren Buffett isn’t close to beating the market this year, and a giant pension fund has cut its investment in Berkshire Hathaway , the investment juggernaut that Buffett helms.
Class B shares of Berkshire Hathaway stock (ticker: BRKb ) have only managed a 0.9% gain so far in 2019 through Friday’s close, in sharp contrast to the S&P 500’s 18.7% rise.
We’ve noted that Buffett suffered “a reputational and financial black eye” earlier this year as Berkshire took a $1 billion paper loss when Kraft Heinz stock (KHZ)—one of its larger investments—tumbled. Years ago, Buffett backed the combination of H.J. Heinz and Kraft Foods Group that created the company.
Oregon’s Public Employees’ Retirement Fund slashed two-fifths of its Berkshire stock investment by selling 141,822 Class B shares in the second quarter. OPERF, as the pension is known, made the disclosure in a form it filed this week with the Securities and Exchange Commission. OPERF, which recently was counted as the 42nd largest public pension in the world by assets, now owns 222,763 Class B Berkshire shares.
Regards,
Ted
https://www.barrons.com/articles/berkshire-hathaway-stock-is-lagging-and-a-giant-pension-just-slashed-its-stake-51563707754

2019 contribution limits are:
401(k): $56K + $6K (catch up) = $62K
SEP: $56K (no catch up provision)
https://www.irs.gov/retirement-plans/cola-increases-for-dollar-limitations-on-benefits-and-contributions
The IRS has not yet announced 2020 figures for retirement plans. If Vanguard provided contribution limits for 2020, they were projections.
Projected for 2020:
401(k): $57K + $6.5K (catch up) = $63.5K
SEP: $57K (no catch up provision)
https://thefinancebuff.com/401k-403b-ira-contribution-limits.html
Again, see Schwab example cited above for comparison between SEP and DB plan. (For a fair comparison, you need to account for the earnings that are added to the DB plan but not to the SEP. This significantly reduces the gap between the two.)

Hi msf thx... What firms do you recommend for db plans? Vanguard
Hi ema
I believe you can have 401k and distribution 18 or 20k annually and you can buy higher aggressive stocks funds in these
My tax adivesor states same as your thoughts have to be 5 or 6% annually returns or you may run into tax issues irs issues
If you don't like plans you can switch to sep-ira 5 yrs later this is what Vanguard advisor told me (56k distribution 2020)

That sounds about right. I believe you could instead project a higher ROR and contribute less. You would still fund the pension plan up to the IRS limit ($225K/year pension @retirement). You would invest for higher returns and wouldn't even have to contribute as much to get the same level of benefits. But see below for risk.
Are you sure that you were being told that you should not invest for higher return, or did your actuaries say that they would use a lower rate of return for projections? They have to use a credible ROR for projections to determine the max you can contribute. The object is to reach the max permitted balance at retirement. The lower the assumed ROR, the more you can contribute, at least initially.
Regardless, the amount you can/must contribute is recalculated annually. If you project a low (but credible) ROR and perform better, your subsequent contributions will be reduced. If you project a higher (still credible) ROR and underperform, your subsequent min contribution requirements may be increased, possibly substantially.
I trust the actuaries explained to you how you are committing to maintaining high contribution levels for several years (otherwise you risk seeing the IRS disqualify your plan).
Here's a 2016 guide from from Schwab with an example of someone age 55, planning to retire at age 65. (See p.3). Schwab also uses a low projected ROR (here, 3.98%). Note that because you're younger (presumably with more years to retirement), all else being equal, you'd be able to contribute less than the $166K shown. So I'm curious where the $250K figure you gave came from.
https://www.schwab.com/public/file/P-1604569/SLS25840-05-ST.pdf

Hello,
I am self employed, and 50 years old. My business started picking up in the last two years and this year I will have significant cash flow which I want to put in a pre-tax account. I have heard that a defined benefit plan can help me contribute as much as $250,000 per year.
However, during the discussion with the actuarial firm, I was told that the investment return of the plan should be low or kept low. This prevents over funding the plan and sizable contributions can be made each year. If the investment returns are high, the size of the contributions can decrease.
Has anyone in this forum encountered this situation before? I am not sure it is wise to invest money at 3-5% growth rate when the market returns are higher.
Thanks.

PRSNX listed ytd returns as +5.1%? ... M* website is a disaster, but their statistic shows PRSNX up ytd by over 7%. What gives? When I log into my own acct, PRSNX shows up ytd +7.37%.

This article presents some thoughts from fund managers together with some investment ideas. A few excerpts:

“It’s hard for me to buy a utility company when I could buy a company like Home Depot,”
With negative bond yields in Japan and Europe, the Fed will likely keep U.S. interest rates low for a “very long time,”
“The low yields in the fixed-income market are making you take risk elsewhere.”
As a result, Clott has been reducing his exposure to Treasuries and adding shares of companies like AT&T Inc (T.N)
Michael Barclay, a portfolio manager of the $15.1 billion Columbia Dividend Income fund, said he is focusing on picking up income in the technology sector because its strong growth rates will allow companies to increase their dividend payments over time.

https://reuters.com/article/us-usa-stocks-weekahead/wall-street-week-ahead-prospect-of-fed-cut-pushing-dividend-investors-into-tech-energy-idUSKCN1UE19T

The fund on the top of the list - VSTSX - has a $5billion minimum (!).

"compared to the flagship bond fund of the others." NEFZX? AUM $7.3B. LSBDX, $10.9B.
"'Dan Fuss pioneered the benchmark-agnostic, multisector approach to fixed-income that has defined the firm’s flagship Loomis Sayles Bond (LSBDX) since 1991." ... said Alfonzo Bruno, Manager Research Analyst at Morningstar.“
https://www.loomissayles.com/internet/InternetData.nsf/0/2F18CD9C1404261D852583F500624095/$FILE/MSTARAWARDSFORINVESTINGEXCELLENCE.pdf
FWIW, over the past five years (7/21/14 to 7/19/19) even NEFZX has outpaced EVABX, 9.21% annualized vs. 9.10%. LSBDX did better, at 11.32%. (It's still possible to coax this info out of M*, though not as easy as before.
As far as beating other funds for the first quarter of 2016 (one quarter, really?), I don't need M* to remind me that Gaffney went swinging for the fences. She was holding even more non-bond securities than LSBDX. For a short time it worked, until it didn't.
M*'s comments on her style: Concentrated bets on commodities have made for a wild ride.... The team ... often chooses to simultaneously invest in several correlated groups of assets .... As most commodity-related fare sold off in 2015, for example, the fund had nearly 20% [equity/bond] exposure ... in addition to 15% of its currency exposure in commodity-related currencies.... This explains the fund’s last place finish within the multisector bond Morningstar Category that year, when it trailed ... by 15 percentage points. ... the same profile ignited the fund’s strong subsequent rally."

Hi @Ted, Let's look at this for a rolling 5 year time span against some other multi sector bond funds. The three I selected, which I own, were PONAX, LBNDX & JGIAX. EVBAX came in a distant fourth and just behind Fuss (and team) with their fund NEFZX which I also own. It will be interesting to see were she lights. Needless to say, I'm not that impressed as EVBAX was once a highly touted flagship bond fund for Eaton Vance and when compared to the flagship bond fund of the others it comes up short. At one time, I was invested in EVBAX after Gaffney took charge and decided, about a year after she came, to move my EVBAX money into LBNDX making it my largest fixed income holding. And, I'm now glad I did. PONAX and JGIAX are funds that I have added to my income sleeve within the past twelve months, or so, as I continue to build an enhance my income sleeve.