The Vanguard FTSE Emerging Markets ETF has slumped nearly 4% in the past week, driven by Turkey's currency crisis.Its top-10 owners include Betterment and Wealthfront, two robo-advisors that predominantly cater to millennials.The value of their combined positions in the ETF, drawn fromthe most recent regulatory disclosures, fell by$66.4 million.Watch the lira trade against the dollar in realtime here.The Turkish lira did not go down on its own when it plunged to record lows.Emerging-market assets from currencies to stocks also sold off as investors wondered what Turkey's currency trouble would mean for other countries.One of the most prominent victims of the drop was the Vanguard FTSE Emerging Markets exchange-traded fund (VWO), a basket of stocks located in China, South Africa, and other developing countries. With $90 billion in net assets, it's a bedrock emerging-market ETF.Its top investors include Betterment and Wealthfront, two of the most popular robo-advisors that help people get involved in the markets at a low cost.The two companies use algorithms to construct portfolios, with VWO a key component. VWO makes up as much as 15% of some portfolios on Betterment, for example.The two companies are the fifth and eighth-largest investors in VWO, according to their most recent regulatory disclosures. Nearly all of Wealthfront's clients85%are under 45, and 55% of Betterment's customers are millennials (generally placed in the 18-35 age range), company spokespeople said.VWO has fallen 3.6% in the past week, dragged by concerns surrounding Turkish firms' ability to repay their dollar-denominated debt. On Monday, $1 cost as much as 7.13 lira, the highest ever; on January 1, Turkish companies only needed 3.79 lira to repay every dollar they had borrowed.VWO's decline since last week Monday has cost Betterment and Wealthfront investors $66.4 million, based on the sizes of their positions in regulatory filings. The Securities and Exchange Commission requires large investors to disclose their largest holdings once a quarter, and so these shares could have changed since the last filings.Even with this paper loss, many analysts don't expect Turkey's woes to cause significant damage to other emerging markets. For one, the country-specific iShares MSCI Turkey ETF crashed 21% last week, versus 3.6% for VWO. It also helped that Vanguard, which manages VWO, had composed the ETF of just 0.9% Turkish assets, limiting the losses for millennial investors."There is a conspicuous lack of contagion as Turkey's afflictions are uniquely unfortunate among MSCI EM nations and EM is not on the hook for Turkish FX debt," Alexander Redman, the head of Credit Suisse's global emerging-market equity strategy, said in a note on Friday.Frank Chaparro contributed reporting.See also:Investors have turned complacent and are in danger of being sideswiped by a 'likely correction' that's approaching, Morgan Stanley saysMOODY'S WARNS: Mutual funds are bleeding cash at an unprecedented rate, and they're increasingly vulnerable to the next market meltdownGOLDMAN SACHS: Big-money investors are dominating the market with the help of 10 stockshere's the list and how they can continue crushing itJoin the conversation about this storyNOW WATCH: What's going on with Elon Musk Click here to read full news..