need more details ...this is a serious matter that can create serious litigation against the individual that purchse that negative seo services. A lawsuit can be based to a combination of existing legal issues.
But everything depends from the details. It can be a variation of unfair competition, fraudulent schemes
cybercriminal acts and much more.
There is Case law like Perfect 10, Inc. v. Ccbill, LLC, 340 F.Supp.2d 1077 (C.D. Cal., 2004) and other cases that can assist and guide the right attorney to assist you in your case..
Disclaimer:Attorney and Fraud Examiner.One of few that are Certified Fraud Examiners (CFE). The information contained in this website is provided for informational purposes only, and should not be construed as a legal advice on any subject. No recipients of content from this site,clients or otherwise,should act or refrain from acting on the basis of any content included in the site without seeking the appropriate legal or other professional advice on the particular facts and circumstances at issue from an attorney licensed in the recipient's state. The content of this website contains general information and may not reflect current legal developments, verdicts or settlements. The Karamanlis Powers Law Offices expressly disclaims all liability in respect to actions taken or not taken based on any or all of the contents of this website, weblogs, twitter, facebook, google+. *the certification is not a specialty recognized by the California State Bar.
More facts and circumstances would be needed to properly evaluate whether you have a cause of action worth pursuing, however, due to the large sums of lost revenue, I would strongly suggest contacting an attorney experienced in this area of law immediately to evaluate your options.
This advice is for INFORMATIONAL PURPOSES only and should not be relied upon as legal advice. No attorney-client relationship shall be formed as a result of the answer above.
I agree with the others that answer would depend upon the nature of the negative SEO. By way of example, simply optimizing one or more other sites that have would the effect of having yours drop in the rankings would not be actionable. On the other extreme, a company misrepresenting itself as its competitor on websites and requesting that valuable backlinks be taken down may warrant a lawsuit on a host of legal theories, including fraud and online impersonation. Unfair competition can also arise in the context of pay-per-click (PPC) marketing, where a competitor causes clicks to be registered against its competitor's ads in an effort to unfairly compete. While search engines typically filter such "invalid clicks," sophisticated competitors may in some cases be able to bypass a search engine's filters. I have represented plaintiff clients asserting claims on both of the above fact patterns, in each case obtaining court orders permitting expedited discovery to determine the identity of the competitor. A variety of other permutations may exist; experienced legal counsel can help you determine whether you have a viable claim and act swiftly to protect your rights.
This answer is provided for informational purposes only, does not create an attorney-client relationship, and is not to be relied upon as legal advice or applied to specific situations. Legal advice is provided only upon execution of a written retainer agreement and after a comprehensive consultation in which all relevant facts are discussed and reviewed.