A company in a developmental stage that either doesn't have an established business plan or has a business plan that revolves around a merger or acquisition with another firm.
These companies are generally speculative in nature and will issue penny stock in order to finance future operations.
According the Securities Act of 1933 (under Rule 419), blank-check companies are required to disclose the terms and conditions of their offering as well as place any funds received from the offering into an escrow account.
Development stage refers to a company that is focusing a majority of its attention on research & development.