BlackRock Inc., parent of the world’s largest ETF sponsor, iShares, filed paperwork with the Securities and Exchange Commission to begin offering its own indexes, a potentially profound shift for a company that controls more than 40 percent of the $1 trillion U.S. exchange-traded market.

It’s still somewhat rare for ETF companies to provide indexes on their own ETFs, though it is done by firms including WisdomTree and Van Eck Global. To do so, greater regulatory disclosure is required in terms of index composition.

“The requested relief to permit a BlackRock Index to be the Underlying Index for a Fund is substantially similar to the relief granted by the Commission to other open-end management investment companies operated as ETFs,” iShares said, citing as precedent providers including WisdomTree, Van Eck, Claymore, HealthShares and IndexIQ.

As things stand, San Francisco-based iShares casts a rather wide net in terms of the indexes its funds are based on, using a variety of providers, including MSCI, Russell, S&P, Barclays, Dow Jones and even FTSE.

BlackRock said in the filing that each of its indexes will be rules based and will comprise equity and/or fixed-income securities, including depositary receipts and/or other assets.

If iShares chooses to segue to its own indexes on existing funds, the effects would reverberate widely in the U.S. ETF industry. After all, the firm now has almost $430 billion in ETF assets, according to data compiled by IndexUniverse. It didn’t shed any light on its long-term intentions in the filing.

In any case, some of its funds, distributed among various providers, are some of the biggest in the world. A brief and incomplete survey illustrates the points. Among the bigger funds are:

• The $31 billion iShares MSCI Emerging Markets Index Fund (NYSEArca: EEM)
• The $24 billion iShares S&P 500 Index Fund (NYSEArca: IVV)
• The $21 billion iShares Barclays TIPS Bond Fund (NYSEArca: TIP)
• The $14 billion iShares iBoxx $ Investment Grade Corporate Bond Fund (NYSEArca: LQD)
• The $12 billion iShares Russell 2000 Index Fund (NYSEArca: IWM)
• The $6.12 billion iShares FTSE/Xinhua China 25 Index Fund (NYSEArca: FXI)
• The $7 billion iShares Dow Jones Select Dividend Index Fund (NYSEArca: NYSEArca: DVY)

The company said in the filing that each BlackRock index will be “transparent.”

It defined transparency as the methodology and the composition of the benchmark being freely available to the public. It also said any change to the methodology will be announced at least 60 days prior to becoming effective; and any changes to constituents of and weightings of each index will be announced at least two  days prior to the reconstitution and rebalance date.

It stressed in the filing that all such changes will be made freely available to the public.

The “BlackRock Index Provider” will be solely responsible for all BlackRock Index compilation, maintenance, calculation, dissemination and reconstitution activities, the filing said.

Fund advisors will be able to enter into a licensing agreement with the BlackRock Index Provider, and will pay any license fees owed to the benchmark provider. The adviser will be able to sublicense its rights under the agreement to each respective fund at no cost to the fund in question, the filing said.