☰You can, and many companies should start there. The difference is what happens to the risk you keep. A raised deductible absorbs losses into operating budgets as they happen: unpriced, unfunded, and invisible until a major event finds them. A captive formalizes the same retention into an insurance company, and the formality is where the value lives. The layer gets priced by an actuary, pre-funded by premium, backed by regulated reserves, and protected by reinsurance above it, so volatility becomes a planned budget line instead of a surprise.
Ownership also captures what a deductible gives away. The savings from a higher deductible leak back into general budgets and disappear; in a captive, the same margin accumulates as surplus that earns investment income and compounds toward the next opportunity. And a captive can do what no deductible can: access reinsurance directly, write coverage the market excludes, and even sell insurance to affiliated parties, meaning the customers, contractors, tenants, and employees connected to your business, when the risk is profitable. Raising a deductible is a decision; a captive is the infrastructure that makes that decision pay dividends.