The Writers Guild of America is accelerating its attack on Endeavor in the investment world as the parent company of WME prepares for an IPO later this year.

The WGA on Tuesday said it issued a bulletin to “potential investors” in Endeavor that details the state of the guild’s fight with Hollywood’s largest talent agencies over the issue of packaging fees and affiliated production and emphasizing the potential of litigation now in play to alter the landscape for large agencies. The WGA said it sent the letter to “hundreds of institutional investors, including hedge funds, mutual funds and pension plans, as well as investment advisors and industry analysts,” according to WGA West research director Laura Blum-Smith.

The WGA asserts that Endeavor’s “conflicted business practices” put the company at risk of losing substantial sources of profit at the guild wages war to eliminate the longstanding industry tradition of talent agencies receiving packaging fees on TV series and independent films from production entities.

“Endeavor is engaged in several conflicted business practices—namely the negotiation of direct payments from clients’ employers in the form of “packaging fees” and expansion into content production and employment of clients—which have led 1,400 television and film writer clients to leave the agency since April and prompted the filing of a lawsuit alleging violations of fiduciary duty and California’s Unfair Competition law,” the WGA stated in the bulletin titled “The Risks of Investing in Endeavor.”

Representatives for Endeavor and WME could not immediately be reached for comment. The WGA on Monday sent a letter to the Securities and Exchange Commission challenging the number of clients that Endeavor stated it had in the prospectus that was filed with the SEC in late May, given that hundreds of writers have exited the agency amid the guild’s larger battle between Hollywood talent agencies. Endeavor disputed the WGA’s claim and stood by the prospectus statement that the company has more than 6,000 clients across WME and IMG.

“Once again, in an attempt to disrupt our business, WGA leadership is misrepresenting the facts,” Endeavor said in a statement on Monday. “Endeavor has clearly stated that it has ‘more than 6,000 clients’. This is not a static number given the fluidity of the client business, and is still accurate today even after the departure of our former writer clients.”