One stock fell 12.64%, the index fell 0.38%: the arithmetic
Alphabet fell 12.64% and Amazon 4.25% on October 29, 2026; the S&P 500 fell 0.38%. The recovery, concentration and volatility arithmetic for a household.
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Wealth
Long-term investing, compounding, behaviour and the practical mechanics of building money over decades.
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Nov 3, 2026
Oct 31, 2026
A $3,400 FSA saves $1,008 at 22%; forfeiting $1,008 is the break-even
The 2026 health FSA limit is $3,400 and the carryover $680. The arithmetic of forfeiture, the grace period and the $7,500 dependent care limit, from the IRS.
Oct 31, 2026
ACA 2027: a single filer at 250% of poverty owes 8.66% of income
The IRS table for 2027 runs from 2.15% to 10.22% of income and stops at 400% of poverty. The out-of-pocket cap is $12,000. Enrollment opens November 1, 2026.
Oct 30, 2026
EE bonds pay 2.40%, but the 20-year doubling makes it 3.53%
Series EE bonds issued May through October 2026 earn 2.40% a year, yet Treasury lifts them to double at 20 years. The step is worth about $3,900 on $10,000.
Oct 29, 2026
A 50%-of-6% match on $80,000 is $2,400, and half is easy to lose
The 2026 401(k) deferral cap is $24,500. The match depends on the plan formula, the paycheck pattern and the vesting clock. The arithmetic, with sources.
Oct 28, 2026
Estate tax 2026: $15 million each, and one form worth $2 million
The 2026 exclusion is $15,000,000 and the annual gift exclusion $19,000. A $20 million estate owes $2,000,000 or $0 depending on one Form 706 election.
Oct 27, 2026
Part D 2027: a $2,400 drug cap, and a premium held at its 6% limit
The 2027 Part D cap is $2,400, up from $2,100. The base premium is $41.33, a 6% rise when the formula gave $94.06. Enrollment closes December 7, 2026.
Oct 20, 2026
10-year TIPS pay 2.74% over inflation. The I bond fixed rate is 0.90%
On October 16, 2026 the Treasury real yield curve put 10-year TIPS at 2.74%, three times the I bond fixed rate. Gap, breakeven, tax and cap, in arithmetic.
Oct 20, 2026
A 13-week T-bill pays 4.19%; the average savings account pays 0.38%
The October 13, 2026 bill auction cleared at 4.185%, exempt from state income tax. The FDIC national savings average for October 2026 is 0.38%.
Oct 20, 2026
A harvested loss is worth 24 cents, 15 cents or nothing per dollar
Capital losses offset gains, then $3,000 of ordinary income a year; the rest carries forward. Rebuy within 30 days and the loss moves into the new basis.
Oct 20, 2026
Backdoor Roth: $92,500 in an old IRA makes 92.5% of it taxable
The IRS taxes a conversion in proportion to all your IRA balances at December 31, not the account converted. The 2026 Roth income limits and the arithmetic.
Oct 20, 2026
2027 tax brackets: not yet published, but 11 of 12 inputs are in
The IRS had not released the 2027 brackets as of October 20, 2026. The formula is public: a chained-CPI average that was 3.2% higher through August 2026.
Oct 20, 2026
Claiming Social Security at 62 pays 70%; at 70 it pays 124%
With full retirement age 67, a $2,000 benefit is $1,400 at 62 and $2,480 at 70. The three ages, the break-even ages and the survivor rule, from SSA's tables.
Oct 16, 2026
September CPI puts the I bond inflation rate at 2.04% for November
The March-to-September CPI-U change is 2.04%, up from 1.67% in May. With a 0.90% fixed rate, the arithmetic gives a 5.00% composite from November 1, 2026.
Oct 16, 2026
Social Security COLA for 2027 is 3.6%: $75 on the average benefit
SSA set the 2027 COLA at 3.6% on October 14, 2026: a CPI-W average of 328.746 against 317.265. The arithmetic, and what changes in January 2027.
Oct 13, 2026
A $26,500 Roth conversion costs $3,180 in 2026. Here is the arithmetic
Rev. Proc. 2025-32 fixes the 2026 brackets. Filling the 12% band, the pro-rata rule on Form 8606 and the two five-year clocks, worked line by line.
Oct 13, 2026
An HSA shelters $4,400 in 2026. The plan it requires can cost $8,500
The 2026 HSA limits, the high-deductible plan rules that come with them, the three tax exemptions in the IRS's own words, and a 20-year illustration.
Oct 13, 2026
529 plans in 2026: $19,000 a year in, up to $35,000 out to a Roth
The 2026 gift exclusion is $19,000, the K-12 cap is $20,000 and the 529-to-Roth limit is $35,000. The state deduction runs from zero to $76,000 a year.
Oct 13, 2026
Medicare Part B is $202.90 a month, and $1 of income can add $1,148
The 2026 Part B premium rose 9.7%. The income surcharge starts at $109,000 and is a cliff, not a slope. 2027 figures were unpublished at October 12, 2026.
Oct 13, 2026
Social Security's $184,500 wage cap is $60,600 times 3.045
The taxable maximum is a 1994 figure scaled by a wage index with a two-year lag, rounded to $300. The arithmetic, and what is unannounced for 2027.
Oct 7, 2026
The $400 test: 63% would pay in cash, stuck there since 2022
In the Fed's 2025 household survey, 63% would cover a $400 emergency with cash or its equivalent and 12% could not pay at all. What the question really asks.
Oct 7, 2026
At 73, a $500,000 IRA must pay out $18,867.92: the RMD arithmetic
The IRS rules on required minimum distributions: the start age under SECURE 2.0, the April 1 trap, the divisor table and the 25% excise tax.
Oct 7, 2026
A couple on $120,000 can owe $0 on $40,000 of long-term gains
The 2026 0% capital gains band runs to $98,900 of taxable income for married couples. Gains stack on top of wages, so wages decide how much fits.
Oct 7, 2026
$7.89 trillion sits in money market funds, none of it FDIC-insured
Money market funds run on SEC Rule 2a-7, not deposit insurance. What the 2023 reforms changed, how a 7-day yield works and what it pays on $10,000.
Oct 7, 2026
The $250,000 FDIC limit applies per category, not per person
Deposit insurance is counted per depositor, per bank, per ownership category. One married couple's accounts at one bank, worked through dollar by dollar.
Oct 7, 2026
At a 22.15% card APR, $5,000 on minimums takes 21 years to clear
The Fed's second-quarter 2026 card-rate reading is 22.15% on accounts charged interest. What that does to a $5,000 balance, month by month, and how prime moves it.
Oct 7, 2026
The I bond's next rate hangs on one CPI number, due October 14
Two CPI-U index levels and a fixed rate Treasury picks make up every I bond rate. We rebuild the formula from the regulation and BLS tables.
Oct 7, 2026
2026 savings limits: $49,750 at age 61, $36,400 at age 45
The IRS limits for 401(k)s, IRAs and HSAs in 2026, how inflation indexing and $500 rounding set them, and what 2027 figures exist so far.
Oct 7, 2026
The COLA formula, two months in: CPI-W is 3.3% above its base
Social Security's COLA is set by three monthly CPI-W readings. July and August 2026 are in; September's arrives October 14. Here is the arithmetic so far.
Sep 28, 2026
The 4% rule was a worst case, not a target: two papers, read closely
Bengen's 1994 paper never used the word SAFEMAX and called 4% the rate that survived the worst 30 years on record. The Trinity tables add the caveats.
Sep 28, 2026
Banks earn 3.90% at the Fed. Savers get 0.37%. The gap, measured
The FDIC's national average savings rate for September 2026 is 0.37%. The Fed pays banks 3.90% on reserves and a 1-year T-bill yielded 4.50% on September 25.
Sep 23, 2026
How to check whether a financial number you just read is still true
Every economic figure has two dates, a publisher, a revision history and an error bar. Four of those five are usually missing from the article you read it in. Here is how to find them in about a minute.
Sep 21, 2026
Pay rose 3.1% in the year to August. Prices rose 3.4%.
Average hourly earnings reached $37.75 in August. Measured against inflation over the same twelve months, the average worker went slightly backwards.
Aug 16, 2026
$10,000 a year ago: bitcoin, gold, and the part return charts never show
One of these turned $10,000 into $13,115. The other turned it into $5,310. The interesting question is not which — it's what you would have had to endure to still be holding.
Aug 15, 2026
What 3.4% inflation actually does to money sitting in a savings account
The arithmetic is simple, rarely done, and slightly uncomfortable. Here it is, with every assumption shown.