As a long time patent prosecutor and litigator (and now startup founder), I believe that many entrepreneurs have a common misunderstanding (and a mistaken perception) about what IP and how such IP can be protected. But for the sake of discussion (since you have provided no info as to what IP you are seeking to protect), if you are seeking protection for the "look and feel" of your website, then copyright might be the venue through which you could protect your website against downstream copycats.
Copyright vests automatically in a work, provided that it satisfies certain criteria. U.S. provides registration procedures via the Library of Congress which must be followed for the author to benefit from full protection. For a work to qualify for copyright in the U.S., it must be "original." This is not an onerous requirement to satisfy. The work does not have to be novel or unique. It just has to originate from the author (i.e., it must not be copied but must be created as a result of some skill, labor and judgement). The work must also be recorded in writing or otherwise but the method of fixation is irrelevant and could even include computer memory.
With this background, if what you are seeking to protect is the "look and feel" of your website, you should consider whether you are the owner of or have the right to use all of the materials that you wish to include in the website (e.g. data, text, photographs and software). If you are not the owner of the materials, you will need a license from the respective copyrighted owner in order to use, alter, and include them on your website.
Now, if what you are actually seeking to protect is the underlying tools, systems, or methods facilitated by the website (again, you have given little to no information so I'm on a hunch here), then patent might be an option. But patent eligibility has become very stringent in the past five years. U.S. Supreme Court and the Patent Office have created a set of specific rules governing patent eligibility. Abstract ideas (which include certain software implementations) are not patent eligible. A website, without more, is not patent eligible. Nor is it the right kind of "IP" for which you can obtain a patent.
As to ownership transfer, no investors would EVER invest in this "new business entity" unless you have transferred your rights to any such "IP" to this business entity. Without such IP, such investors are basically investing in an empty shell.
A lesson to be learned is Coverplay. Coverplay was looking to raise about 350k from angel investors. A few investors made proposals and one particular investor offered Coverplay's founders 350k in exchange for 40% of their company. Coverplay countered with 350k in exchange for 30% of the company and 10% of the patent. The investors huddled and then pulled their deals off the table because this indicated to them that Coverplay didn't own the patent.
Without the IP, there was no business. The investors (rightfully) assumed the patent was owned by the company. In essence, Coverplay was asking for investment in something they didn't own. Many entrepreneurs are claiming they own the IP when they really don't legally.
When starting a new business entity involving IP, you must transfer the IP to this new business entity. For example, if the intellectual property is developed prior to incorporation, you can transfer the IP via the founder's stock purchase and tech transfer agreement.