One of my strategies in Global-Investing is to buy attractive relatively small company shares listed abroad, because of their growth or yield features. Fund managers who have to buy heavily in liquid, listed stocks, focus on large-caps.

However my strategy is proving ever more difficult lately because of quirks in world market pricing. Market pricing is the sacred cow of modern day investment theory and economic order—and performance.

But it depends on a factor hard to properly evaluate, exchange rates. Most small caps trade heavily on a local market, but often their American Depositary Receipts are obscure and trade rarely. The marketmaker, supposedly making a market in these shares no longer does so, leaving investors with little price guidance except what is happening on the foreign market for the ordinary shares. To actually trade abroad from a US on-line discount brokerage is pricey, with exchange fees, currency fees, and special handling requirements.

The main reason why marketmakers are falling down on the job is the volatility of foreign exchange rates against the US dollar. In one day last month the Japanese Yen, the currency of a major foreign market, jumped 4% in a flash crash. That meant every single Japanese stock on Wall Street was instantly down 4% (because the currency created fewer dollars.)

Particularly annoying is the way this spilled over into Hong Kong, China's market door to the world. The HK$ used to be fixed in stone, but encroaching Beijing pressures led this currency to fluctuate too.

While this is an extreme case it is not unique. ADRs were first created in the 1920s to enable Americans to buy British shares. The back and forth between Britain and EU over British exit causes huge short-term movements in sterling, thereby scaring off marketmakers for the largest ADR market, for British stocks. And Irish or Chilean or Dutch shares listed or co-listed in London are also heavily affected—Irish particularly because the Dublin market is tiny.

The Euro is not immune either. Anything from Italian populism to Spain cracking down on Catalans, from green demonstrators in Germany to yellow vest ones in France, impact the common currency. So marketmakers opt out of posting prices and stocks from major euro-markets are hard to price here.

Brokerages are themselves partly to blame. Because they have cut commission to the bone to compete, they no longer will pay foreign bourses for price information that would enable them and their customers to bypass market makers at a plausible US price.

Further discouraging global portfolios, the US discount brokerages like E-trade since the start of the year no longer let their clients view the trading in major foreign markets like Tokyo, Hong Kong, London, Paris, Frankfurt, or even (God help us) Toronto.

Fidelity and Schwab offers price info but then warns customers that this will not necessarily be the price at which trades are booked, despite their supposed legal and advertised right to bust a trade which did not take place under the best terms.

And it is not just individual shares. Multi-asset fund managers, who offer investors a way to avoid the full horrors of volatility and currency flukes, are also affected. Their performance has been dismal during the most recent market selloff and recovery. Natixis Investment Managers of France, perhaps not neutral commentators, warn that this can happen again in European markets, Latin America, and the Pacific Rim. I do not imagine that robots would do better despite the trend toward artificial intelligence is asset management.

Meanwhile closed-end fund trackers often buy and sell these funds for their own clients' benefit, using non-public information because coverage of this niche in the market is no longer profitable for publications like Barron's. (Managers of open-end and exchange-traded funds pay to buy ads but closed-end funds are barred from advertising.) The result is that CEFs, which often trade at attractive discounts from net asset value, are increasingly hard to price because value data is not publicly available. Overlap between the CEF trackers and funds of funds or managed accounts makes it harder to use this vehicle to go global.

As for bonds, the information gap is traditional and huge because there are way too many bonds out there for any generalist publication to cover. And traders cheat a lot.