With its eye on the small and midsized defined contribution markets, BlackRock, Inc., has broadened its lineup of index mutual funds for defined contribution plans.

“Now, with our enhanced lineup, we can help those that prefer to implement (index strategies) through their use of mutual funds,” Chip Castille, head of BlackRock’s U.S. and Canada defined contribution group, said in a press release.

It’s expected that the share of defined-contribution assets in index investments will grow from 11% in 2005 to 20% by 2015, according to research firm Cerulli Associates. The result would be allocations closer to those typically seen in defined benefit plans. BlackRock recently added nine LifePath index portfolios as well as its All Country World Index ex U.S. Fund. That brings to 16 its slate of core index mutual funds available to sponsors. The newest funds join a product suite that includes index funds such as the S&P 500 Stock Fund, Small Cap Index Fund and International Index Fund.

“They are on the right path here,” Aite Group LLC senior analyst Greg Cherry said of BlackRock’s index push in the small and midsized defined contribution space.

But he cautioned that a shift to index products by small-and mid-size plan sponsors is likely to be slow and gradual. “I don’t see a quick upturn,” he said. “I see it as more of a longer-term upward shift.”

One reason is that advisors, often the gatekeepers into such plans, tend to be more interested in recommending actively managed products in an effort to show they’re adding value, Cherry added.

At the same time, indexing promises a transparent, low-cost and low-maintenance investment solution for defined-contribution plans and their participants.

“In my mind, the tension lies between the rational cost element versus advisor preference, and even the platform preference,” Cherry said.

BlackRock is an indexing giant. As of June 30 2011, the company managed more than $2 trillion in index-based products spanning equity, fixed income, multi asset and alternative investment strategies.

The company also takes credit for creating the first target date funds, in 1993, under its LifePath brand. It offers access to the strategies primarily to mega- and large defined-contribution plans. The strategies are offered in collective trust structures with minimum investments above the mid- and small-plan market range. With the nine newest LifePath Index Portfolios, delivered in a mutual fund structure, the company is bringing its indexing and target-date expertise to smaller clients.

The addition of LifePath index portfolios means that BlackRock now offers both active and index versions of its LifePath portfolios in a mutual fund offering for DC plans.