Something is fishy about that story.
"125,000 high-income earners"
"did not file tax returns going back to 2017" (that is 7 years of missed returns)
"the agency says hundreds of millions of dollars of unpaid taxes are involved in these cases"
OK, let's assume it's $999,999,999 in collectible money. Divide that by the 125,000ppl and we're looking at $8k per person. And then divide that by the 5 (actually 7) years of missed taxes and those "high-income earners" owed just ~$1600 each year? The details don't make sense.
"Beginning this week, the IRS will start sending out noncompliance letters to more than 25,000 people who earn more than $1 million per year and 100,000 people with incomes between $400,000 and $1 million who failed to pay their taxes between 2017 and 2021."
Assuming a very modest 10% federal tax/year on the lowest bracket of their income:
25,000 x $100k tax/year x 5 years: $12.5B
100,000 x $40k tax/year x 5 years: $20.0B
Shouldn't they be saying "the agency says 30 billion dollars of unpaid taxes are involved in these cases"