Top shelf municipal bonds rallied on Friday, traders said, with yields on some maturities falling by as much as 19 basis points to record lows after Britain voted to leave the European Union.

The yield on 10-year benchmark muni general obligation fell 16 to 19 basis points from 1.53% on Thursday, while the 30-year muni yield declined 15 to 18 basis points from 2.23%, according to a read of Municipal Market Data's triple-A scale.

"I expect business as usual for munis after the dust of today's rally settles. Despite a reset to lower yields, next week's new issue calendar should see the same strong demand experienced in recent weeks, with mutual fund inflows continuing in future weeks," said Alan Schankel, municipal strategist at Janney Montgomery Scott.

Betterment has stated its decision to delay trading after the Brexit vote was done "with the best interest of our clients at the forefront." (Bloomberg News)
Betterment has stated its decision to delay trading after the Brexit vote was done "with the best interest of our clients at the forefront." (Bloomberg News)

U.S. Treasuries were also rallying Friday. The yield on the two-year Treasury declined to 0.64% from 0.77% on Wednesday, while the 10-year Treasury yield dropped to 1.57% from 1.74% and the yield on the 30-year Treasury bond decreased to 2.42% from 2.56%.

U.S. equities were following European stocks lower. The Dow Jones was off about 2%, the S&P was down around 2.25% and the Nasdaq was almost 3% lower. U.K. equities were off about 2.5% while stocks fell in Germany by over 6% and by more than 5% in France.

On Thursday, the 10-year muni to Treasury ratio was calculated at 88.1% compared to 89.1% on Wednesday, while the 30-year muni to Treasury ratio stood at 87.3% versus 87.7%, according to MMD.