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London CNN Business  — 

The US stock market rally has in many ways been befuddling. But there’s no denying that gains have been extraordinary.

The index just notched its strongest 50-day rally of all time as investors opt to look past the risks associated with rising US-China tensions and widespread civil unrest in the United States.

What’s happening: Since March 23, when the index hit its recent low, the S&P 500 has gained 39.6%. That’s the strongest increase ever across 50 trading days, according to Ryan Detrick, senior market strategist at LPL Financial.

“There’s an old market saying that equities take the stairs up and the elevator down, but in the latest market cycle, the elevator up was almost as fast as the way down,” analysts at Bespoke Investment Group told clients.

Detrick noted on Twitter that stocks were higher both six and 12 months after the seven other largest 50-day rallies. But that happening again is an extremely tough call to make given widespread uncertainty about the trajectory of Covid-19, the lack of guidance on corporate earnings and the fractious US political environment.

“The key in our view is that we do not end up in a negative spiral which is typical of recessions, between weak final demand, falling profits, weak labor market, weak credit markets and low oil [prices],” JPMorgan equity strategist Mislav Matejka said in a note to clients this week. He also noted his concern that the US-China relationship could sour again.

There are signs of rising tensions between Washington and Beijing. The US government said Wednesday that it will block Chinese airlines from flying into the country, claiming that China hasn’t allowed US carriers to resume these routes.

China’s civil aviation regulator on Thursday issued a notice that effectively allows US carriers to resume limited service into the country. But it’s not clear this will be enough for the Trump administration to back down.

The spat highlights the ongoing risks that the US-China relationship could devolve significantly even before the US presidential election. Analysts previously thought that a trade truce struck late last year would at least hold through November.

And for JPMorgan’s Matejka, it’s not the only worry.

“While we were bullish the whole of 2019, and most of the last 10 years, we believe that current risk-reward for equities is not too attractive,” he said.

The wall of stimulus money keeps growing

Governments and central banks keep throwing money at worst global downturn since the Great Depression in hopes of fueling a recovery in the second half of this year.

The latest: Germany’s government has approved a €130 billion ($146 billion) stimulus package to kickstart its recovery, ensuring that Europe’s largest economy will add to its short-term relief efforts with significant longer-term spending.

“Now that the lockdown is reaching an end we need to make sure that everyone has the courage to invest again and to make sure that consumer demand rises again,” finance minister Olaf Scholz said.

Investors have welcomed the move, while warning that policymakers can only do so much.

“The fiscal response to the crisis is getting closer to textbook. It is powerful and decisive,” Bank of America Europe economists Evelyn Herrmann and Ruben Segura-Cayuela told clients Thursday. “But a large export sector still means only partial healing if the rest of the world doesn’t recover.”

ECB time: Attention now turns to European Central Bank President Christine Lagarde. Investors believe that the ECB will significantly expand its coronavirus-era bond buying program, providing more support. Bank of America’s team warns that expectations are extremely high, however, leaving room for disappointment.

Global banks wade into the Hong Kong minefield

Two of the world’s top banks are backing a controversial national security law that is poised to drastically broaden China’s power over Hong Kong.

HSBC and Standard Chartered this week signaled support for the bill drafted by Beijing that will be imposed in coming months. The lenders joined other major businesses in Hong Kong voicing support for the law.

“We respect and support laws and regulations that will enable Hong Kong to recover and rebuild the economy and, at the same time, maintain the principle of ‘One Country, Two Systems,’” HSBC said in a post on Chinese social media.

HSBC is headquartered in London, but was founded in Hong Kong and has a major business presence in China. Hong Kong and China are by far the bank’s biggest moneymakers; last year, the divisions pulled in enough money to wipe out losses in the United Kingdom and keep the company profitable.

The UK-based Standard Chartered, meanwhile, said in a statement that the proposed national security law “can help maintain the long-term economic and social stability” of the city.

Why it matters: The companies are among a growing list of major businesses in Hong Kong that have come out in a show of support for the contentious legislation.

Up next

J.M. Smucker (SJM) reports results before US markets open. Broadcom (AVGO), Gap (GPS) and Slack (WORK) follow after the close.

Also today:

  • Initial and continuing US unemployment claims for the last week post at 8:30 a.m. ET.
  • The European Central Bank announces its latest monetary policy decision at 7:45 a.m. ET.

Coming tomorrow: The latest US employment report is expected to show that the American economy shed another 8 million jobs last month.