Nasdaq OMX Group (NDAQ) and S&P Dow Jones Indices are shopping for acquisitions to bolster their index offerings in what could be a sign of an imminent wave of consolidation for indexing space.

Executives from both companies “told Reuters in recent interviews that they would be interested in looking at bidding on index businesses that come to market.

Nasdaq now has over $1 trillion in assets tracking its various indices, Reuters reported. One of the largest ETFs benchmarked to a Nasdaq Index is the PowerShares QQQ (QQQ) , also known as the “Nasdaq 100 tracking ETF.”

NASDAQ OMX Global Indexes also offers a suite of dividend indices which are used by popular dividend ETFs such as the Vanguard Dividend Appreciation ETF (VIG) . The new First Trust NASDAQ Rising Dividend Achievers Index (RDVY) is also benchmarked to a Nasdaq dividend index. [These High Achieving Dividend Indices Delivered in 2013]

Reuters also reported that Barclays is mulling a sale of its index business and its expected MSCI (MSCI), Bloomberg, Thomson Reuters, FTSE and Markit could take a look at that operation.

While most ETF providers use third-party indices, some are increasingly using their own in-house indices. For example, the bulk of WisdomTree’s (WETF) ETFs are linked to the firm’s own indices and Market Vectors has, in recent years, converted a growing number of its ETFs to its own indices. [Nuclear Energy ETF Gets New Index]

In addition to S&P 500 ETFs, popular ETFs benchmarked to S&P Dow Jones Indices include th e SPDR S&P Dividend ETF (SDY) and the nine sector SPDR ETFs issued by State Street Global Advisors.

S&P’s indices have grown significantly in the past year (McGraw-Hill Finance) with improved margins, which prompted Terry McGraw III to state in his last earnings conference call: “That is just a testimony to what a fabulous, fabulous business this is.”