Common Mortgage Indices
Last Updated August 9, 1999
here are many indexes used for adjustable rate mortgages (ARMs).
The three most common indexes are:
- 1 Year US Treasury Security Adjusted to a Constant Maturity (CMT)
- Cost of Funds of the 11th District Federal Home Loan Bank (COFI)
- London InterBank Offering Rate (LIBOR) -- Monthly
The following graph and table compare the three common indexes.

1999 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
4.51 |
4.70 |
4.78 |
4.69 |
4.85 |
5.10 |
5.03 |
|
|
|
|
|
| COFI |
4.61 |
4.56 |
4.52 |
4.49 |
4.48 |
4.50 |
|
|
|
|
|
|
| LIBOR |
4.95 |
5.00 |
4.94 |
4.90 |
4.93 |
5.22 |
5.18 |
|
|
|
|
|
1998 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
5.24 |
5.31 |
5.39 |
5.38 |
5.44 |
5.41 |
5.36 |
5.21 |
4.71 |
4.12 |
4.53 |
4.52 |
| COFI |
4.98 |
4.97 |
4.92 |
4.90 |
4.88 |
4.88 |
4.91 |
4.89 |
4.88 |
4.76 |
4.69 |
4.66 |
| LIBOR |
5.70 |
5.79 |
5.72 |
5.69 |
5.69 |
5.75 |
5.69 |
5.73 |
5.40 |
5.27 |
5.05 |
5.12 |
1997 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
5.61 |
5.53 |
5.80 |
5.99 |
5.87 |
5.69 |
5.54 |
5.56 |
5.52 |
5.46 |
5.46 |
5.53 |
| COFI |
4.82 |
4.76 |
4.78 |
4.82 |
4.86 |
4.85 |
4.89 |
4.90 |
4.94 |
4.96 |
4.95 |
4.96 |
| LIBOR |
5.46 |
5.47 |
5.72 |
5.70 |
5.71 |
5.72 |
5.64 |
5.68 |
5.67 |
5.63 |
5.76 |
5.85 |
1996 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
5.09 |
4.94 |
5.34 |
5.54 |
5.64 |
5.81 |
5.85 |
5.85 |
5.83 |
5.55 |
5.42 |
5.47 |
| COFI |
5.03 |
4.98 |
4.87 |
4.84 |
4.82 |
4.81 |
4.82 |
4.84 |
4.83 |
4.84 |
4.84 |
4.84 |
| LIBOR |
5.47 |
5.35 |
5.45 |
5.45 |
5.45 |
5.52 |
5.49 |
5.43 |
5.44 |
5.38 |
5.39 |
5.55 |
1995 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
7.05 |
6.70 |
6.43 |
6.27 |
6.00 |
5.64 |
5.59 |
5.75 |
5.62 |
5.59 |
5.43 |
5.31 |
| COFI |
4.75 |
4.93 |
5.01 |
5.06 |
5.14 |
5.18 |
5.14 |
5.13 |
5.11 |
5.17 |
5.20 |
5.06 |
| LIBOR |
6.08 |
6.13 |
6.14 |
6.08 |
6.06 |
6.08 |
5.89 |
5.91 |
5.92 |
5.84 |
6.03 |
5.74 |
1994 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
3.54 |
3.87 |
4.32 |
4.82 |
5.31 |
5.27 |
5.48 |
5.56 |
5.76 |
6.11 |
6.54 |
7.14 |
| COFI |
3.71 |
3.69 |
3.63 |
3.67 |
3.73 |
3.80 |
3.86 |
3.95 |
4.04 |
4.19 |
4.37 |
4.59 |
| LIBOR |
3.14 |
3.59 |
3.70 |
3.94 |
4.38 |
4.56 |
4.52 |
4.88 |
5.00 |
5.08 |
6.00 |
5.99 |
1993 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
3.50 |
3.39 |
3.33 |
3.24 |
3.36 |
3.54 |
3.47 |
3.44 |
3.36 |
3.39 |
3.58 |
3.61 |
| COFI |
4.36 |
4.33 |
4.24 |
4.17 |
4.10 |
4.05 |
4.00 |
3.96 |
3.88 |
3.82 |
3.82 |
3.88 |
| LIBOR |
3.20 |
3.20 |
3.20 |
3.14 |
3.20 |
3.20 |
3.19 |
3.20 |
3.19 |
3.19 |
3.58 |
3.30 |
1992 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
4.15 |
4.29 |
4.63 |
4.30 |
4.19 |
4.17 |
3.60 |
3.47 |
3.18 |
3.30 |
3.68 |
3.71 |
| COFI |
6.00 |
5.80 |
5.61 |
5.43 |
5.29 |
5.26 |
5.07 |
4.87 |
4.80 |
4.60 |
4.51 |
4.43 |
| LIBOR |
4.14 |
4.25 |
4.25 |
3.97 |
4.07 |
3.92 |
3.39 |
3.50 |
3.19 |
3.28 |
3.17 |
3.34 |
1991 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
6.64 |
6.27 |
6.40 |
6.24 |
6.13 |
6.36 |
6.31 |
5.78 |
5.57 |
5.33 |
4.89 |
4.38 |
| COFI |
7.86 |
7.84 |
7.65 |
7.50 |
7.33 |
7.15 |
7.00 |
6.84 |
6.71 |
6.57 |
6.41 |
6.24 |
| LIBOR |
6.97 |
7.06 |
6.33 |
6.08 |
5.95 |
6.08 |
5.95 |
5.75 |
5.50 |
5.25 |
4.81 |
4.24 |
1990 ARM Indices
| Index |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| CMT |
7.92 |
8.11 |
8.35 |
8.40 |
8.32 |
8.10 |
7.94 |
7.78 |
7.76 |
7.55 |
7.31 |
7.05 |
| COFI |
8.37 |
8.40 |
8.26 |
8.26 |
8.17 |
8.09 |
8.11 |
8.07 |
8.09 |
8.05 |
8.04 |
7.96 |
| LIBOR |
8.13 |
8.38 |
8.38 |
8.56 |
8.31 |
8.33 |
8.06 |
8.13 |
8.30 |
7.94 |
9.13 |
7.64 |
|