Update 2 (2:20 pm ET): The Mexican peso has sunk to its lowest level of the session on reports that the Trump Administration is studying options for a border closure, including a partial shutdown of all entry points into the US.
Here's more from BBG:
Officials are discussing the possibility of closing select ports of entry, partly closing them, or shutting all entry points entirely, said the official, who asked for anonymity to comment on private deliberations. The preparations are said to be somewhere between a theoretical discussion of options and implementation planning.
It's just the latest sign that Trump is serious about closing the border, despite the objection from the Wall Street Journal editorial board.
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Update: A White House spokesman said that "progress has been made" on the border issue, while AMLO, the Mexican president, said it's good the US "realizes we're helping" on immigration.
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Anxieties about a possible order to close the US-Mexico border eased somewhat on Tuesday when President Trump lauded Mexican authorities on Tuesday for finally "apprehending large numbers of people at the border"...
After many years (decades), Mexico is apprehending large numbers of people at their Southern Border, mostly from Guatemala, Honduras and El Salvador. They have ALL been taking U.S. money for years, and doing ABSOLUTELY NOTHING for us, just like the Democrats in Congress!— Donald J. Trump (@realDonaldTrump) April 2, 2019
...However, it appears the president has changed his mind once again, renewing his threat to close the border "if no action" is taken, and provoking some modest weakness in the Mexican peso as traders worried about the impact to trade.
Congress must get together and immediately eliminate the loopholes at the Border! If no action, Border, or large sections of Border, will close. This is a National Emergency!— Donald J. Trump (@realDonaldTrump) April 3, 2019
Notably, Trump in his latest tweet shifted the object of blame from the Mexican government to Congress, which he demanded must "immediately eliminate the loopholes at the Border!"
Since November, Trump has periodically threatened to close the border, though few took these threats seriously until last week, when Trump said he could shut the border "for a long time" in the very near future, as the number of migrants crossing into the US has soared to a record high, straining local resources and overflowing customs and border patrol detention facilities.
The peso weakened on the headline, sliding toward its lows of the session.