By Greg Burns | Chicago’s last major stand-alone exchange crossed a milestone Thursday in its long-delayed effort to demutualize and launch an initial public offering.

The Chicago Board Options Exchange has submitted S-1 and S-4 documents with the Securities and Exchange Commission for an IPO of up to $300 million, setting the stage for a required membership vote in coming weeks, and potentially an IPO at mid-year.

The Chicago company, CBOE Holdings Inc., did not say when it plans to go public or how many shares it hopes to sell.

The exchange filings were halted for years as a result of intramural battles with the Chicago Board of Trade, founder of the CBOE, and Board of Trade parent CME Group Inc. Lengthy litigation over trading privileges known as “exercise rights” ended with a settlement last year.

In a meeting at the Futures Industry Association trade show in Florida, CBOE Chief Executive William Brodsky said the filings were “consistent with what we’ve talked about in the past. This is the culmination of many, many months of work.”

The plan is silent on the number of shares to be issued, and their price range. The proposal calls for demutualization and an IPO to proceed concurrently, by June 30.

– The Associated Press contributed to this report