Real estate investor Stephen Rosenberg once had an open checkbook for Democrats running for higher office, including Hillary Clinton.

That changed after Donald Trump was elected president. Since then, Rosenberg has created a shell company that so far is dedicated to only supporting Trump for his 2020 reelection campaign.

Rosenberg's company, SR 2018 LLC, is listed as a six-figure donor to the Trump Victory committee, a joint fundraising operation that divvies up funds between the campaign and the Republican National Committee. The company's name consists of Rosenberg's initials, while the mailing address of the LLC is identical to that of his real estate investment firm, Greystone, which is located in the Carnegie Hall Tower in New York.

After an extensive search in New York's corporate database, no names matching SR 2018 were found. However, Delaware's Division of Corporations did list a company with the same name as Rosenberg's. The filing shows the company has an annual tax assessment of $300.

Rosenberg and a spokeswoman for the Trump campaign did not return requests for comment.

Wealthy donors sometimes use shell companies as a way to anonymously finance campaigns. The Center for Responsive Politics, which tracks the owners of these types of companies and who they're supporting, describes a limited liability company associated with GOP billionaire Bruce Kovner that recently gave $35,500 to the National Republican Congressional Committee. Like Rosenberg's firm, Kovner's uses his initials as the company name.

Delaware is one of the preferred states to create a shell company due to corporate-friendly laws and a judicial system that is known to efficiently resolve business litigation.

The $360,600 donation to Trump Victory came in May and, on another filing with Rosenberg's name as the contributor, a memo cites SR 2018, describing the company's contribution as "permissible funds." The shell company has also given directly to Trump's campaign with two separate max checks of $2,800, with one going toward the primary stage of the election cycle and the other for the later general election.