Self-Employment. One consequence of owning a disregarded entity LLC is that it most likely makes you liable for self-employment tax. In essence, however, this is only a shifting of what would ordinarily be the employer's share of Medicare and Social Security tax to the owner of the business.
http://info.legalzoom.com/disregarded-entity-llc-3551.html
Self-Employment Tax. An individual owner of an LLC classified as a disregarded entity is not an employee of the company. Rather, the owner is subject to self-employment tax on the earnings from the LLC. The self-employment tax is in addition to income tax, though 50 percent of the self-employment tax is deductible.
http://smallbusiness.chron.com/llc-disregarded-entity-3645.html
The Internal Revenue Service treats a single-member Limited Liability Company as a disregarded entity for federal income tax purposes. This means that the sole member of an LLC files his taxes in the same way that sole proprietors do. Nonetheless, single-member LLCs may receive certain types of payments that are reportable to the IRS by the payer on an information return, such as on a 1099 form. If your LLC receives one of these payments, in all likelihood, you’ll need to fill out a W-9 form for the payer.
http://info.legalzoom.com/fill-out-w9-llc-disregarded-company-23441.html
A disregarded entity refers to a business entity with one owner that is not recognized for tax purposes as an entity separate from its owner. A single-member LLC (SMLLC), for example, is considered to be a disregarded entity. For federal and state tax purposes, the sole member of a SMLLC disregards the separate legal status of the SMLLC otherwise in force under state law. As the result of being disregarded, the SMLLC does not file a separate tax return.
http://www.kfmr.com/what-is-a-disregarded-entity/
Tip. If you contract services from a disregarded LLC you should send them a 1099 form as the IRS likely views the owner as a single entity and subject to the self-employment tax. Sending a 1099 is especially important if the disregarded LLC owner files his taxes with his Social Security Number.
http://smallbusiness.chron.com/disregarded-llc-3623.html
Step 1. Enter your name and the LLC’s legal name on the first two lines of the W-9. On the first line is where you insert the name you file your tax returns under.
http://info.legalzoom.com/fill-out-w9-llc-disregarded-company-23441.html
This means that most LLCs are disregarded entities for federal tax purposes. Nevertheless, an LLC can elect to be taxed as a corporation by filing Form 8832. Upon the effective date of the election, the company loses its status as a disregarded entity. An LLC that is taxed as a corporation, however, may qualify as an S corp, in which case it would again be a disregarded entity.
http://info.legalzoom.com/disregarded-entity-llc-3551.html
Identification. A disregarded LLC refers to a LLC owned by a single member, according to the IRS. Unless a single-member LLC chooses otherwise, the IRS treats it as a sole proprietorship and does not tax the LLC. Instead, profits from the LLC flow through the owner's personal taxes.
http://smallbusiness.chron.com/disregarded-llc-3623.html
Disregarded by IRS. The IRS classifies a single-member LLC by default as a disregarded entity and treats the business as a sole proprietorship for income tax purposes. The IRS disregards the company as being separate from its owner.
http://smallbusiness.chron.com/llc-disregarded-entity-3645.html
Step 2. Check the appropriate box for your tax classification. The tax classification relates to the type of taxation your LLC earnings are subject to. Despite the fact your legal entity is an LLC, check the “Individual/sole proprietor” box – not the “limited liability company” box.
http://info.legalzoom.com/fill-out-w9-llc-disregarded-company-23441.html
what is a llc disregarded entity?
LLC disregarded entity is a  business entity with one owner that is not recognized for tax purposes as an entity separate from its owner. A Limited Liability Company disregarded entity is a business entity with one owner that is not recognized for tax purposes as an entity separate from its owner.