An offer letter is often the only employment document, which makes its drafting consequential.
At-will statement. Clear, and not undermined elsewhere in the letter. References to annual salary, to a first-year bonus, or to a probationary period after which employment becomes permanent, have each been read as promises of duration.
Compensation. State the pay rate in the period actually used — hourly or biweekly rather than annual, where at-will status matters — and describe bonus and commission as governed by a plan that may be amended.
Contingencies. Employment conditioned on background check, references, work authorisation, and where lawful, a drug test. State that the offer is withdrawn if any is not satisfied.
Equity. Describe as subject to board approval and to the plan and award agreement, and avoid stating a value.
Benefits. Described as subject to plan terms and to change.
Restrictive covenants. Where the employee will be asked to sign one, say so in the offer letter and attach it. Presenting a non-compete on the first day, after the employee has resigned elsewhere, raises consideration problems in several states and is prohibited by statute in others.
Start date and reporting line, and a statement that the letter is the entire agreement on these subjects.