How to handle initials at the end of a sentence

I came across this sentence:

"They are only distributed in the U.S. Payment occurs in a similar fashion to mag-stripe, without a PIN and often in off-line mode..."

On reading the first time, I got confused by "U.S. Payment." It seemed to be the name of an organization, but the subsequent words were out of place. So I re-read and realized that "Payment" was the start of a new sentence.

Is there a way to disambiguate the period at the end of "U.S." so it is immediately obvious that the sentence has ended, or do we have to rely on context ?

There are several things you can do here:

"The U.S. is the only place they are distributed. Payment occurs in a similar fashion to mag-stripe, without a PIN and often in off-line mode..."

"They are only distributed in the U.S.; payment occurs in a similar fashion to mag-stripe, without a PIN and often in off-line mode..."

"They are only distributed in the US. Payment occurs in a similar fashion to mag-stripe, without a PIN and often in off-line mode..."

"They are only distributed in the United States. Payment occurs in a similar fashion to mag-stripe, without a PIN and often in off-line mode..."

Using or omitting periods in the abbreviation of state and country names will be determined by the style guide you use. (The Chicago Manual of Style recommends not using periods.)

But there's often no problem with using a semicolon, and you can always choose to spell out the long name.