# fdladder Fixed deposit and bond ladder builder for conservative savers in India. Give it an amount, an investor profile, a liquidity schedule and a rate card, and it designs a ladder across bank FDs, small finance bank FDs, corporate FDs, T-bills, G-secs, RBI floating rate bonds and tax-free bonds. The ladder meets every planned withdrawal, respects per-bank caps and the DICGC Rs 5 lakh limit, and maximises post-tax value. It also tracks existing deposits: maturity calendar, FY-wise interest and TDS statements for ITR and Form 26AS reconciliation, and an iCal export. ## Features - Instrument maths with Indian bank conventions: simple interest below six months, quarterly compounding with exact broken periods, non-cumulative monthly/quarterly payouts, effective yield, premature withdrawal, T-bill discount/yield/price, G-sec YTM (Newton) with accrued interest. - Tax engine: FY-wise accrual, TDS per bank (Rs 40,000 / Rs 50,000 senior, 20% without PAN, Form 15G/H), Section 80TTB, tax-free bonds, old vs new regime comparison. - MILP optimizer (scipy/HiGHS) with liquidity constraints, per-bank caps, DICGC limits, minimum deposit sizes and minimum corporate rating; classic equal-rung ladder generator for comparison. - Reinvestment simulation under flat, falling (-1 point) and rising (+1 point) rate scenarios: single long FD vs ladder vs optimizer vs debt fund. - Holdings tracker with upcoming-maturity alerts and iCal export. ## Install ```bash uv venv .venv uv pip install -p .venv/bin/python -e '.[dev]' ``` Python 3.12+. Runtime dependencies: click, rich, pyyaml, numpy, scipy. ## Quickstart ```bash .venv/bin/fdladder plan examples/plan.yaml --rates examples/rates.csv .venv/bin/fdladder compare examples/plan.yaml --rates examples/rates.csv .venv/bin/fdladder holdings examples/holdings.csv --fy 2026-27 --senior --slab 20 .venv/bin/fdladder calendar examples/holdings.csv --ical -o maturities.ics .venv/bin/fdladder calc fd --amount 500000 --rate 7.25 --days 400 --senior ``` The rate card in `examples/rates.csv` contains illustrative numbers and fictional issuers. They are not live rates. ## Usage ### `fdladder calc fd` Single-instrument calculator. `--senior` adds `--senior-premium` (default 0.50) to the rate and uses the senior TDS threshold and 80TTB. ``` $ fdladder calc fd --amount 100000 --rate 7.25 --days 400 --start 2026-01-15 ┌──────────────────────────────────┬──────────────────────────────────────────────────────────────┐ │ Rate applied │ 7.25% │ │ Convention │ quarterly compounding, simple interest for the broken period │ │ Maturity value │ ₹108,196 │ │ Interest │ ₹8,196 │ │ Effective annual yield │ 7.45% │ │ Premature close at day 200 │ ₹103,459 (rate - 1%) │ │ Tax at slab (if all in one year) │ ₹2,557 │ │ Post-tax yield │ 5.13% │ └──────────────────────────────────┴──────────────────────────────────────────────────────────────┘ Interest by financial year ┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━┓ ┃ FY ┃ Interest accrued ┃ TDS (this bank alone) ┃ ┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━┩ │ 2025-26 │ ₹1,510 │ ₹0 │ │ 2026-27 │ ₹6,687 │ ₹0 │ └─────────┴──────────────────┴───────────────────────┘ ``` Non-cumulative payout (`--payout monthly|quarterly`): ``` $ fdladder calc fd --amount 120000 --rate 7.2 --days 365 --payout monthly --start 2026-04-01 ┌──────────────────────────────────┬─────────────────────────────────────────┐ │ Rate applied │ 7.20% │ │ Convention │ monthly payout, interest not compounded │ │ Monthly payout │ ₹716 │ │ Total interest │ ₹8,589 │ │ Maturity proceeds │ ₹120,716 │ │ Tax at slab (if all in one year) │ ₹2,680 │ │ Post-tax yield │ 5.04% │ └──────────────────────────────────┴─────────────────────────────────────────┘ Interest by financial year ┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━┓ ┃ FY ┃ Interest accrued ┃ TDS (this bank alone) ┃ ┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━┩ │ 2026-27 │ ₹8,589 │ ₹0 │ └─────────┴──────────────────┴───────────────────────┘ ``` Other options: `--slab`, `--cess`, `--regime`, `--no-pan`, `--form15`, `--other-income`, `--penalty`. ### `fdladder calc tbill` and `calc gsec` ``` $ fdladder calc tbill --days 91 --discount 6.25 ┌──────────────────┬──────────────────────────────┐ │ Price │ 98,441.7808 per 100,000 face │ │ Discount rate │ 6.2500% │ │ Investment yield │ 6.3489% │ └──────────────────┴──────────────────────────────┘ $ fdladder calc gsec --coupon 7.26 --maturity 2033-08-22 --settle 2026-10-16 --price 101.25 ┌──────────────────┬──────────┐ │ Clean price │ 101.2500 │ │ Accrued interest │ 1.0890 │ │ Dirty price │ 102.3390 │ │ YTM │ 7.0245% │ └──────────────────┴──────────┘ ``` `tbill` takes exactly one of `--price`, `--discount`, `--yield`; `gsec` takes exactly one of `--price`, `--ytm`. ### `fdladder plan PLAN.yaml --rates RATES.csv` Builds an allocation (`--strategy optimizer|ladder|both`, default optimizer; `--json` for machine output) and prints the allocation, the liquidity check, FY-wise interest and tax, expected TDS per payer and the regime comparison. Plan file format: see `examples/plan.yaml`. ``` $ fdladder plan examples/plan.yaml --rates examples/rates.csv Plan: ₹2,500,000 for 1825 days from 2026-04-01, senior citizen, old regime at 20% + 4% cess Allocation (optimizer) ┏━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓ ┃ Issuer ┃ Type ┃ Tenor ┃ Rate ┃ Amount ┃ Matures ┃ Maturity value ┃ Post-tax yield ┃ ┡━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩ │ Sample Public Bank A │ bank_fd_cumulative │ 183d │ 6.90% │ ₹23,000 │ 2026-10-01 │ ₹23,803 │ 5.59% │ │ Sample │ bank_fd_cumulative │ 183d │ 6.75% │ ₹112,000 │ 2026-10-01 │ ₹115,823 │ 5.46% │ │ Cooperative-style Bank │ │ │ │ │ │ │ │ │ F │ │ │ │ │ │ │ │ │ Sample Public Bank A │ bank_fd_cumulative │ 440d │ 7.25% │ ₹176,000 │ 2027-06-15 │ ₹191,928 │ 5.91% │ │ Sample Public Bank A │ bank_fd_cumulative │ 731d │ 7.10% │ ₹245,000 │ 2028-04-01 │ ₹282,085 │ 5.82% │ │ Sample Small Finance │ sfb_fd │ 731d │ 8.40% │ ₹2,000 │ 2028-04-01 │ ₹2,362 │ 6.92% │ │ Bank D │ │ │ │ │ │ │ │ │ Sample Public Bank A │ bank_fd_cumulative │ 1825d │ 7.00% │ ₹1,000 │ 2031-03-31 │ ₹1,415 │ 5.85% │ │ Sample Private Bank B │ bank_fd_cumulative │ 1825d │ 7.30% │ ₹348,000 │ 2031-03-31 │ ₹499,652 │ 6.11% │ │ Sample Private Bank C │ bank_fd_cumulative │ 1825d │ 7.25% │ ₹349,000 │ 2031-03-31 │ ₹499,859 │ 6.07% │ │ Sample Small Finance │ sfb_fd │ 1825d │ 7.75% │ ₹339,000 │ 2031-03-31 │ ₹497,599 │ 6.51% │ │ Bank D │ │ │ │ │ │ │ │ │ Sample Small Finance │ sfb_fd │ 1825d │ 8.10% │ ₹334,000 │ 2031-03-31 │ ₹498,745 │ 6.82% │ │ Bank E │ │ │ │ │ │ │ │ │ RBI Floating Rate Bond │ rbi_frb │ 1825d │ 7.45% │ ₹391,000 │ 2031-03-31 │ ₹391,000 + payouts │ 5.99% │ │ Savings / liquid │ liquid │ - │ 3.00% │ ₹180,000 │ on demand │ - │ 2.38% │ │ reserve │ │ │ │ │ │ │ │ └────────────────────────┴────────────────────┴───────┴───────┴──────────┴────────────┴────────────────────┴────────────────┘ Liquidity check (post-tax cash vs withdrawals + reserve) ┏━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━┓ ┃ Date ┃ Needed ┃ Available ┃ OK ┃ ┡━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━┩ │ 2026-04-01 │ ₹180,000 │ ₹180,000 │ yes │ │ 2026-10-01 │ ₹330,000 │ ₹330,198 │ yes │ │ 2027-06-15 │ ₹530,000 │ ₹530,349 │ yes │ │ 2028-04-01 │ ₹830,000 │ ₹830,078 │ yes │ └────────────┴──────────┴───────────┴─────┘ Financial-year interest and tax ┏━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━━━━━━┓ ┃ FY ┃ Interest ┃ Tax-free ┃ 80TTB ┃ Tax at slab ┃ TDS ┃ Net payable ┃ ┡━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━━━━━━┩ │ 2026-27 │ ₹172,014 │ ₹0 │ ₹50,000 │ ₹25,379 │ ₹2,913 │ ₹22,466 │ │ 2027-28 │ ₹167,266 │ ₹0 │ ₹50,000 │ ₹24,391 │ ₹2,921 │ ₹21,470 │ │ 2028-29 │ ₹153,699 │ ₹0 │ ₹50,000 │ ₹21,569 │ ₹2,913 │ ₹18,656 │ │ 2029-30 │ ₹163,456 │ ₹0 │ ₹50,000 │ ₹23,599 │ ₹2,913 │ ₹20,686 │ │ 2030-31 │ ₹173,483 │ ₹0 │ ₹50,000 │ ₹25,684 │ ₹2,905 │ ₹22,779 │ └─────────┴──────────┴──────────┴─────────┴─────────────┴────────┴─────────────┘ TDS expected (for Form 26AS reconciliation) ┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━┓ ┃ FY ┃ Payer ┃ Interest ┃ Threshold ┃ TDS ┃ ┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━┩ │ 2026-27 │ RBI Floating Rate Bond │ ₹29,130 │ ₹10,000 │ ₹2,913 │ │ 2027-28 │ RBI Floating Rate Bond │ ₹29,209 │ ₹10,000 │ ₹2,921 │ │ 2028-29 │ RBI Floating Rate Bond │ ₹29,129 │ ₹10,000 │ ₹2,913 │ │ 2029-30 │ RBI Floating Rate Bond │ ₹29,130 │ ₹10,000 │ ₹2,913 │ │ 2030-31 │ RBI Floating Rate Bond │ ₹29,050 │ ₹10,000 │ ₹2,905 │ └─────────┴────────────────────────┴──────────┴───────────┴────────┘ Post-tax value at horizon (2031-03-31): ₹2,532,021 post-tax IRR: 5.91% Tax on this plan over the horizon by regime: old ₹120,623 (slab 20%), new ₹86,311 (slab 10%) ``` ### `fdladder compare PLAN.yaml --rates RATES.csv` ``` $ fdladder compare examples/plan.yaml --rates examples/rates.csv Post-tax value at horizon and IRR (₹2,500,000, 1825 days; scenarios shift reinvestment rates by -1 / +1 point) ┏━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓ ┃ Strategy ┃ flat: value ┃ IRR ┃ falling: value ┃ IRR ┃ rising: value ┃ IRR ┃ Shortfall ┃ Early closures ┃ ┡━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩ │ single long FD │ ₹2,488,909 │ 5.58% │ ₹2,488,909 │ 5.58% │ ₹2,488,909 │ 5.58% │ ₹0 │ 2 │ │ ladder │ ₹2,458,399 │ 5.34% │ ₹2,449,420 │ 5.27% │ ₹2,467,469 │ 5.41% │ ₹0 │ 0 │ │ optimizer │ ₹2,533,020 │ 5.92% │ ₹2,532,847 │ 5.92% │ ₹2,533,195 │ 5.92% │ ₹0 │ 0 │ │ debt fund │ ₹2,502,498 │ 5.68% │ ₹2,397,708 │ 4.85% │ ₹2,611,470 │ 6.51% │ ₹0 │ 0 │ └────────────────┴─────────────┴───────┴────────────────┴───────┴───────────────┴───────┴───────────┴────────────────┘ Shortfall and early closures are shown for the flat scenario. ``` The single long FD has to break deposits early for the withdrawals (see the early closure count); the debt fund wins when rates rise and loses when they fall; the optimizer's liquidity-matched ladder is the least sensitive to the scenario because its reinvestment is small. See `docs/optimizer.md` for how the simulation works. ### `fdladder holdings HOLDINGS.csv --fy 2026-27` Interest accrued in the FY per deposit, TDS per payer, tax at slab, and an alert list of maturities within `--within` days (default 60). Tax options: `--senior --slab 20 --cess 4 --regime old|new --no-pan --form15 --other-income N`. `--asof` fixes the alert date. ``` $ fdladder holdings examples/holdings.csv --fy 2026-27 --senior --slab 20 --asof 2026-10-16 --within 90 Holdings interest, FY 2026-27 ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓ ┃ Issuer ┃ Type ┃ Principal ┃ Rate ┃ Start ┃ Maturity ┃ Interest in FY ┃ ┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩ │ Sample Public Bank A │ bank_fd_cumulative │ ₹500,000 │ 7.25% │ 2025-04-10 │ 2026-11-20 │ ₹25,186 │ │ Sample Public Bank A │ bank_fd_cumulative │ ₹300,000 │ 7.00% │ 2025-09-01 │ 2027-09-01 │ ₹22,445 │ │ Sample Private Bank B │ bank_fd_cumulative │ ₹400,000 │ 7.60% │ 2025-06-15 │ 2026-12-15 │ ₹23,200 │ │ Sample Private Bank B │ bank_fd_noncumulative │ ₹200,000 │ 6.90% │ 2025-10-05 │ 2028-10-05 │ ₹13,721 │ │ Sample Small Finance Bank D │ sfb_fd │ ₹450,000 │ 8.60% │ 2025-12-01 │ 2027-02-01 │ ₹34,226 │ │ Sample Finance Co (AAA) │ corporate_fd │ ₹300,000 │ 7.90% │ 2025-08-01 │ 2028-08-01 │ ₹25,718 │ │ Government of India (T-bill) │ tbill │ ₹200,000 │ 6.50% │ 2026-08-01 │ 2026-10-31 │ ₹3,241 │ │ Sample PSU Tax-free Bond │ taxfree_bond │ ₹500,000 │ 5.60% │ 2024-03-01 │ 2029-03-01 │ ₹28,000 │ │ (secondary) │ │ │ │ │ │ │ └────────────────────────────────────┴───────────────────────┴───────────┴───────┴────────────┴────────────┴────────────────┘ TDS statement, FY 2026-27 (reconcile with Form 26AS) ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━┓ ┃ Payer ┃ Type ┃ Interest ┃ Threshold ┃ TDS ┃ ┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━┩ │ Government of India (T-bill) │ tbill │ ₹3,241 │ no TDS │ ₹0 │ │ Sample Finance Co (AAA) │ corporate_fd │ ₹25,718 │ ₹5,000 │ ₹2,572 │ │ Sample PSU Tax-free Bond (secondary) │ taxfree_bond │ ₹28,000 │ no TDS │ ₹0 │ │ Sample Private Bank B │ bank_fd_cumulative │ ₹23,200 │ ₹50,000 │ ₹0 │ │ Sample Private Bank B │ bank_fd_noncumulative │ ₹13,721 │ ₹50,000 │ ₹0 │ │ Sample Public Bank A │ bank_fd_cumulative │ ₹47,631 │ ₹50,000 │ ₹0 │ │ Sample Small Finance Bank D │ sfb_fd │ ₹34,226 │ ₹50,000 │ ₹0 │ └──────────────────────────────────────┴───────────────────────┴──────────┴───────────┴────────┘ Total interest ₹175,738 (tax-free ₹28,000), 80TTB deduction ₹50,000, tax at slab ₹20,329, TDS ₹2,572, net payable ₹17,758 hint: total income looks within the nil-tax limit; Form 15H can stop TDS next year. Maturities from 2026-10-16 within 90 days ┏━━━━━━━━━━━━┳━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓ ┃ Date ┃ In ┃ Issuer ┃ Type ┃ Proceeds ┃ Account ┃ ┡━━━━━━━━━━━━╇━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩ │ 2026-10-31 │ 15d │ Government of India (T-bill) │ tbill │ ₹203,241 │ Retail Direct │ │ 2026-11-20 │ 35d │ Sample Public Bank A │ bank_fd_cumulative │ ₹561,490 │ joint with spouse │ │ 2026-12-15 │ 60d │ Sample Private Bank B │ bank_fd_cumulative │ ₹447,868 │ self │ └────────────┴─────┴──────────────────────────────┴────────────────────┴──────────┴───────────────────┘ ``` ### `fdladder calendar HOLDINGS.csv` Maturity table (`--within N`, `--asof DATE`), or an iCalendar file with `--ical` (stdout, or `-o file.ics`; `--alarm-days` sets the reminder lead time, default 7). ``` $ fdladder calendar examples/holdings.csv --ical --asof 2026-10-16 --within 40 BEGIN:VCALENDAR VERSION:2.0 PRODID:-//fdladder//maturities//EN CALSCALE:GREGORIAN BEGIN:VEVENT UID:GovernmentofIndia(T-bill)-tbill-2026-08-01-200000-2026-10-31@fdladder DTSTAMP:20261016T000000Z DTSTART;VALUE=DATE:20261031 SUMMARY:Government of India (T-bill) tbill matures: Rs 203\,241 DESCRIPTION:Principal 200\,000 at 6.50% from 2026-08-01. Maturity proceeds 203\,241. Retail Direct BEGIN:VALARM ACTION:DISPLAY DESCRIPTION:Government of India (T-bill) tbill matures: Rs 203\,241 TRIGGER:-P7D END:VALARM END:VEVENT BEGIN:VEVENT UID:SamplePublicBankA-bank_fd_cumulative-2025-04-10-500000-2026-11-20@fdlad der DTSTAMP:20261016T000000Z DTSTART;VALUE=DATE:20261120 ... ``` ## Input files **Plan YAML** (`examples/plan.yaml`): `amount`, `start_date`, `horizon_years` or `horizon_days`; `investor` (age, `slab_rate` as a number or `{old, new}`, `regime`, `other_income`, `has_pan`, `form15`, `dicgc_capacities`, `cess_pct`); `liquidity` (`withdrawals` list of date/amount/note, `emergency_reserve_months`, `monthly_expenses`); `preferences` (`max_per_bank`, `max_per_bank_pct`, `only_dicgc_insured`, `min_rating`, `idle_rate`, `liquidity_weight`, `ladder_rungs`, `lot`). **Rate card CSV** (`examples/rates.csv`, lines starting with `#` are ignored): `issuer, type, tenor_min_days, tenor_max_days, rate, senior_premium, compounding, penalty_pct, rating, min_amount`. One row per tenor band. `type` is one of `bank_fd_cumulative`, `bank_fd_noncumulative`, `sfb_fd`, `corporate_fd`, `tbill`, `gsec`, `rbi_frb`, `taxfree_bond`. `compounding` is `quarterly` (cumulative), `payout_monthly`, `payout_quarterly`, `half_yearly` (coupon bonds) or `discount` (T-bills). **Holdings CSV** (`examples/holdings.csv`): `issuer, type, principal, rate, start_date, maturity_date, compounding, penalty_pct, account`. Type and compounding may be blank (cumulative bank FD, quarterly). ## Architecture | Module | Role | | --- | --- | | `instruments.py` | Pure maths: FD values, payouts, T-bill, bond price/YTM, xirr | | `models.py` | `Instrument`, `Position`, `Plan`, `TaxProfile`, `Allocation` and their cash flows | | `taxes.py` | FY accrual, TDS thresholds, Form 15G/H, 80TTB, FY statements | | `ratecard.py`, `planio.py`, `tracker.py` | CSV/YAML loading and validation, candidate generation, maturity calendar | | `valuation.py` | Linear per-rupee coefficients shared by optimizer and ladder | | `optimizer.py`, `ladder.py` | MILP allocation and equal-rung generator | | `evaluate.py` | Post-tax value, liquidity check, exposures, FY statements for an allocation | | `simulate.py`, `planner.py` | Reinvestment simulation and strategy comparison | | `ical.py` | RFC 5545 export | | `cli.py` | Click commands and rich rendering | Deeper notes: [`docs/formulas.md`](docs/formulas.md), [`docs/tax-rules.md`](docs/tax-rules.md), [`docs/optimizer.md`](docs/optimizer.md). ## Tests ```bash .venv/bin/pytest ``` 100 tests covering hand-computed FD values (including broken periods), payout formulas, FY accrual splits, TDS thresholds per bank (senior, no PAN, Form 15), T-bill and YTM maths, property-based tests (hypothesis) that the optimizer satisfies liquidity, bank caps, DICGC limits and minimum amounts, the ladder generator, reinvestment scenarios, iCal output and the CLI end to end. ## Limitations - Rates are user input; the sample card is illustrative. - Bank calculators differ from the 365/4-day quarter convention by a few rupees. - The optimizer applies slab tax to interest; 80TTB and TDS timing appear in the statements only. - Bonds are modelled as bought at par and held to maturity; premature closure of non-cumulative deposits and bonds is simplified. - The RBI bond TDS threshold is an assumption. Verify tax rules before relying on any figure; this is a planning aid, not tax or investment advice. See `docs/optimizer.md` for the complete list.