Liquid net worth counts only the assets you could actually spend soon. Cash and savings accounts, money market funds, stocks and funds in a regular brokerage account, and vested company shares that are not locked up all count. A house, a car, a 401(k), and unvested stock do not, or count only partially, because turning them into cash takes time, costs money, or is not possible yet.
The reason to track it separately from total net worth is that emergencies and opportunities happen in cash. A $600,000 net worth that is $450,000 of home equity and $130,000 of retirement accounts leaves $20,000 of liquid net worth, which is a fragile position if a layoff lasts six months. A $300,000 net worth with $120,000 in a brokerage account is far more resilient.
How to treat retirement accounts is a judgment call. Some people count Roth IRA contributions, which can be withdrawn without penalty. Most exclude traditional 401(k) and IRA balances because early withdrawal costs income tax plus a 10% penalty, so a $100,000 balance might yield $60,000 in hand.
Vested RSUs count, minus the tax on selling and any trading-window restrictions your company imposes. Unvested RSUs never count.
The common mistake is feeling wealthy based on total net worth while running out of room month to month. If liquid net worth is less than a few months of expenses, the emergency fund comes before anything else.