"The economy's current account is in long-term decline and the future growth of the economy will be increasingly dependent on foreign capital," said the investment bank in a report on Tuesday.
The last time China had a current account deficit was in 1993. A country may need to operate on borrowed means when it runs into a deficit as the total value of goods, services and investments it imports exceeds the total value it exports.
Unlike 1993, however, the investment bank predicts that the shift toward a shortfall might be "sustained," setting the world's second biggest economy on a path to becoming more reliant on foreign capital from 2020 onward.
China's current account surplus has slipped from 10.3 percent of its GDP in the third quarter of 2017, to just 0.4 percent in the third quarter of 2018. This year, the current account deficit could be 0.3 percent of its GDP, and widen to 0.6 percent in 2020, the investment bank predicted.
That pales in comparison to its golden days more than a decade ago, when China had a huge current account surplus of $420 billion, or 9.9 percent of its GDP in 2007.
The report blamed the shrinking current account on China's aging population, and plateauing market share in goods exports, among other factors.
"We expect China to shift to an annual current account deficit from 2019 onwards due to a slipping national saving rate amid an aging population," said the bank.
A deficit means that a country is spending more than it is getting in income. And if the country's national savings rate is declining, then it would have to attract more foreign capital to fund its needs.
Besides a shrinking share in exports, there has also been rising domestic demand for imported goods and outbound tourism, which has exacerbated the narrowing surplus, according to the report.
In addition to that, China is experiencing a slowdown. Official government figures said the country's economy slowed last year to 6.6 percent — the lowest expansion rate in 28 years.
With the gloomy outlook, Morgan Stanley estimated that China will require at least $210 billion of net foreign capital inflows per year from 2019 to 2030 in order to finance the shortfall. That funding gap would initially be between $50 billion and $90 billion a year from 2019 to 2020, but would widen gradually to $200 billion in 2020, the bank estimated.
"This means that China will need to improve its business environment further and attract (foreign direct investment) inflows, accelerate opening up of the domestic equity and bond markets, and promote RMB's status as an international reserve currency," it said, referring to another name for the Chinese yuan.
But investors can seize some opportunities amid those developments.
Morgan Stanley is overweight on China stocks.
"Inflows into China's equity markets will likely rise thanks to growth in the A-share market cap over the long run … A stabilisation in China growth this year would also help to encourage inflows, and we see more gains," the report said.
It also recommended that investors buy the stock of Hong Kong Exchanges and Clearing (HKEX), the city's stock exchange operator. The bank explained that rising stock and bond portfolio flows will lead to rising revenues for the operator, helping its stock do well over the next two to three years.