Why an offer letter is an iceberg
The part of a job offer that fits on one page — base, bonus, equity — is maybe 40% of the decision. The other 60% lives in the benefits PDF, the employee handbook, the IP assignment addendum, and the things no one writes down (like whether the VP you would report to is about to leave). This checklist surfaces the pieces that move the actual financial and career outcome.
Real example. A senior engineer got two offers last quarter: $260,000 TC at a Series D startup, $240,000 TC at a public company. The startup number looked $20,000 better. But: the startup's 401(k) had no match ($6k/yr gone), health plan was HDHP-only with no HSA contribution ($3k/yr gone), PTO was "unlimited" which in practice meant 14 days vs 25 ($9k/yr gone), and the equity cliff was 18 months instead of 12. Net: the $240,000 public offer was worth more on day one and every day after. The candidate took the public role and banked the difference.
The 401(k) match is the most underrated negotiation lever
Most candidates do not look at the 401(k) match. They should. A 6% dollar-for-dollar match on a $150,000 salary is $9,000/year of pre-tax money — equivalent to a $12,000-13,000 pre-tax salary bump. Over 10 years at 7% growth, that's $125,000 in an account you own.
Also check the vesting schedule. A 6% match that vests over 4 years graded (0%, 33%, 67%, 100%) means if you leave at year 2, you forfeited two years of match. Immediate vesting is candidate-friendly and increasingly common — ask for it.
Use the 401(k) Match vs Raise Calculator to see the compounded difference in your specific numbers.
Equity due diligence in 15 minutes
For RSUs at a public company, the math is simple: shares × current price = dollar value. Vesting is almost always 4-year 25/25/25/25 with quarterly or monthly cadence. The hard part is the refresh: companies quote a big initial grant and then a smaller annual refresh. If you're modeling year-5 TC and you only get the initial grant, you'll face an "equity cliff" where pay drops 30-40%.
For private company stock options, ask four questions. (1) Total shares outstanding (fully diluted)? (2) What's the last 409A valuation per share? (3) What's the last preferred share price? (4) What's the strike price on my options? With those four numbers you can model outcomes. For example: 20,000 options at $2 strike, company last raised at $8/share preferred, 409A at $3/share — your options have $1/share in "fair value" tax basis and could 4x to $8 or go to zero. Don't count the moonshot.
Use the Stock Option Value Calculator and RSU Value Calculator before you sign.
Red flags that justify walking
High turnover. Check LinkedIn: in the team you're joining, how many people have left in the last 18 months? If more than 40% of the team shows 1-2 year tenures and external exits, you're joining a churn environment. Ask the hiring manager directly.
Vague equity. "A meaningful grant" without a number, or a refusal to state total shares outstanding at a private company, is a deal-breaker. You cannot model what you cannot see.
Rushed timelines. "We need a yes by end of week" without a real constraint (offer expiration, hiring freeze, fiscal cutoff) is a pressure tactic. Push back. If they cannot give you 48 hours, they are not a good-faith negotiator.
Refusal to document. Any term — remote flexibility, reporting line, title, bonus, equity — that gets promised verbally but isn't in the written offer does not exist. Say: "Let's just make sure this is in the letter." If they refuse, that's your answer.
Due diligence sources in 2026
The good comp data sources as of this year: Levels.fyi for tech (individual contributor level data, verified), Glassdoor for mid-market cross-function benchmarks, Payscale for role + city medians, Robert Half salary guide for finance/ops/legal, SHRM and BLS for HR and government roles. Cross-reference three sources before you anchor.
For company health: Glassdoor reviews (read the 1-star reviews, not the 5-star ones), Blind for tech-specific insider perspectives, Fishbowl for consulting and finance, LinkedIn for attrition signals (who left, how long they stayed), Crunchbase for startup funding history, SEC 10-K for public company risk factors.
Run the offer through the Total Compensation Analyzer to get one comparable number.
What this checklist does not cover
Industry-specific terms you should look up separately: in law firms, partnership track and billing requirements; in medicine, RVU structures and call obligations; in PE/VC, carry allocation and catch-up mechanics; in academia, tenure clock and teaching load; in consulting, up-or-out thresholds and class-year comparisons.
This checklist also does not model taxes on your specific situation. Use the Take-Home Pay Calculator after you pick one or two finalists to see the post-tax reality in your state. Two offers $20k apart in gross can be $6-9k apart in net after state tax differences between, say, Texas and California.
One question to ask at the end of every offer call
"What is the one thing about this role I should know that is not written on the offer letter?" Good recruiters will answer honestly (the team is under a tight deadline, the VP is new, the product is pivoting). Evasive recruiters will deflect — and that itself is data.
The offer letter is a contract. The call is where the real signal lives. Take notes.
Disclaimer
This is not legal or financial advice. Employment contracts vary by jurisdiction and employer. Terms like non-competes, IP assignment, arbitration clauses, and severance rights are subject to state law changes that happen every year. If the offer involves equity at a private company, deferred compensation, or unusual contractual provisions, consult an employment attorney before signing. This checklist is a starting point, not a substitute for legal review on a high-stakes contract.