How to readh "teffects nnmatch"

[Yasutake Homma]

Hello Statalist,

I am analyzing bond yield difference in between of foreign currency and domestic currency.

I have dataset as follows:

Yield
Amount
Maturity
Rating
Foreign = 1 if it is issued in foreign or zero otherwise

Then, I ran
teffects nnmatch (Yield Amount Maturity) (Foreign)
tebalance sum

The result shows

Raw Matched
-----------------------------------------
Number of obs = 1,461 2,922
Treated obs = 42 1,461
Control obs = 1,419 1,461
-----------------------------------------

The option of teffects nmatch should be nneighbor (1) so I should have matched 1:1, I thought.
But I am confused at the tebalance result showing Matched Treated obs = 1461 and Control obs 1461.

So in this case, can I say "to match the T and C with the nearest distance of coveriates, Stata expands Treated observation and Control obs to 1461 each?
If you could tell me how I can read the tebalance sum result, it would be highly appreciated.

Regards;