<PAGE>
SUPPLEMENT DATED FEBRUARY 11, 1999, TO
THE PROSPECTUS DATED MAY 1, 1998, FOR
STRATEGIC ADVANTAGE II VARIABLE UNIVERSAL LIFE
A FLEXIBLE PREMIUM VARIABLE LIFE INSURANCE POLICY
ISSUED BY
SECURITY LIFE OF DENVER INSURANCE COMPANY
AND ITS
SECURITY LIFE SEPARATE ACCOUNT L1
THIS SUPPLEMENT UPDATES CERTAIN INFORMATION CONTAINED IN YOUR
PROSPECTUS.
PLEASE READ IT CAREFULLY AND KEEP IT WITH YOUR PROSPECTUS FOR FUTURE
REFERENCE.
The following information is added to the prospectus under the section headed,
"Group or Sponsored Arrangements," page 36.
ENHANCED DEATH BENEFIT CORRIDOR OPTION
For policies issued under group or sponsored arrangements, with guaranteed
issue rates, on or after March 15, 1999, an additional benefit option is
available. The policyowner may elect, at any time prior to the issuance of
the policy, the enhanced death benefit corridor option.
After March 15, 1999, existing group or corporate owners of Strategic
Advantage II policies which have guaranteed issue rates, can elect to add
this option to their policies if it is added to all existing policies within
that issue group. If you would like to do this, you should contact your
registered representative/agent or our customer service center for
instructions. Requests to add this option to existing policies will be
honored if they are received by us or our agent by May 15, 1999.
This option generally provides an opportunity for an increased death benefit
on the life of the insured person at certain ages. Under death benefit
options 1 and 2 the account value is multiplied by a factor shown in
Appendix A or B. The result of this calculation is the base death benefit
if it exceeds the stated death benefit. Under the enhanced death benefit
corridor option, the calculation uses the factor shown on the attached new
Appendix A-Enhanced and Appendix B-Enhanced (depending on which definition
of life insurance is in effect for your policy). The result of this
calculation is then used to determine the base death benefit as described
under DEATH BENEFIT OPTIONS, PAGE 20.
There is no separate charge for this feature. However, the same account
value may generate a higher base death benefit under policies with this
option than on policies not electing the option. Cost of insurance charges
are based on the net
<PAGE>
amount at risk, which is the difference between the account value and the
base death benefit. Therefore, as a result of the increased death benefit,
the cost of insurance charges may be higher for policies electing this
option. Your registered representative/agent can provide you with a
personalized illustration to show the difference between a policy with this
option and one without it. If your policy does not have sufficient account
value, electing this option may have no effect on the base death benefit.
Adding this option to your policy does not affect the operation of your
policy's riders, including the Adjustable Term Rider. When the base death
benefit exceeds the stated death benefit, transactions which reduce your
account value (such as a partial withdrawal) also reduce the death benefit.
The dollar reduction to the death benefit under these circumstances is
greater for policies with the enhancement option than on those without the
option.
Once elected, this option cannot be deleted from your policy. You may lose
the benefit of this option if your account value falls below the minimum
level needed to keep it in effect. Once elected, this option continues as
long as coverage on the original insured person continues. If there is a
change of insured person under the right to change insured person
rider, the enhanced death benefit corridor option must be elected on the
application for the new insured person if you want it to be effective. SEE
RIGHT TO CHANGE INSURED RIDER, PAGE 23 AND RIGHT TO EXCHANGE POLICY, PAGE
29.
The following change is hereby made to the last sentence of the first full
paragraph on page 23 under the section, "Adjustable Term Insurance Rider."
"resulting from compliance with the Federal income tax law definition of
life insurance test chosen" is deleted.
<PAGE>
APPENDIX A -- ENHANCED
ENHANCED DEATH BENEFIT CORRIDOR
FACTORS FOR THE
CASH VALUE ACCUMULATION TEST
FOR A LIFE INSURANCE POLICY
<TABLE>
<CAPTION>
Attained Male or Unisex | Attained Male or Unisex
Age Unisex 100/0 (I) Female 80/20 (II) | Age Unisex 100/0 (I) Female 80/20 (II)
-------- ---------------- ------ ---------- | -------- ---------------- ------ ---------
<S> <C> <C> <C> <C> <C> <C> <C>
0 11.727 14.234 12.149 | 36 3.920 4.586 4.037
1 11.785 14.209 12.194 | 37 3.793 4.437 3.906
2 11.458 13.815 11.857 | 38 3.670 4.293 3.780
3 11.128 13.417 11.515 | 39 3.553 4.154 3.658
4 10.803 13.023 11.178 | 40 3.439 4.021 3.541
5 10.481 12.635 10.845 | 41 3.330 3.894 3.429
6 10.161 12.253 10.514 | 42 3.226 3.771 3.322
7 9.844 11.875 10.187 | 43 3.125 3.654 3.218
8 9.530 11.505 9.863 | 44 3.028 3.541 3.119
9 9.221 11.141 9.545 | 45 2.936 3.432 3.023
10 8.918 10.784 9.233 | 46 2.846 3.328 2.931
11 8.623 10.436 8.928 | 47 2.761 3.227 2.843
12 8.338 10.098 8.634 | 48 2.678 3.129 2.758
13 8.066 9.771 8.353 | 49 2.599 3.035 2.676
14 7.808 9.455 8.085 | 50 2.522 2.945 2.597
15 7.564 9.150 7.831 | 51 2.449 2.858 2.522
16 7.335 8.857 7.592 | 52 2.378 2.774 2.449
17 7.118 8.575 7.364 | 53 2.311 2.693 2.379
18 6.911 8.302 7.148 | 54 2.246 2.615 2.312
19 6.713 8.038 6.939 | 55 2.184 2.540 2.248
20 6.521 7.782 6.737 | 56 2.125 2.468 2.187
21 6.334 7.534 6.540 | 57 2.068 2.398 2.128
22 6.150 7.293 6.347 | 58 2.014 2.330 2.071
23 5.969 7.059 6.158 | 59 1.962 2.265 2.017
24 5.791 6.831 5.971 | 60 1.912 2.201 1.965
25 5.615 6.611 5.788 | 61 1.864 2.139 1.915
26 5.441 6.396 5.608 | 62 1.818 2.079 1.867
27 5.271 6.188 5.431 | 63 1.774 2.022 1.821
28 5.104 5.986 5.258 | 64 1.732 1.967 1.777
29 4.940 5.791 5.089 | 65 1.692 1.914 1.735
30 4.781 5.601 4.925 | 66 1.654 1.863 1.695
31 4.626 5.418 4.765 | 67 1.617 1.815 1.657
32 4.476 5.241 4.610 | 68 1.583 1.769 1.620
33 4.330 5.069 4.459 | 69 1.550 1.724 1.585
34 4.188 4.902 4.314 | 70 1.518 1.681 1.552
35 4.052 4.742 4.173 |
</TABLE>
<PAGE>
APPENDIX A -- ENHANCED (CONT.)
ENHANCED DEATH BENEFIT CORRIDOR
FACTORS FOR THE
CASH VALUE ACCUMULATION TEST
FOR A LIFE INSURANCE POLICY
Attained Male or Unisex
Age Unisex 100/0 (I) Female 80/20 (II)
-------- ---------------- ------ ----------
71 1.503 1.655 1.535
72 1.488 1.631 1.519
73 1.475 1.607 1.504
74 1.462 1.585 1.490
75 1.451 1.564 1.477
76 1.441 1.545 1.466
77 1.432 1.527 1.455
78 1.424 1.510 1.445
79 1.416 1.495 1.436
80 1.409 1.480 1.428
81 1.378 1.440 1.395
82 1.348 1.402 1.363
83 1.319 1.366 1.333
84 1.291 1.332 1.304
85 1.265 1.300 1.276
86 1.241 1.270 1.250
87 1.216 1.241 1.225
88 1.194 1.214 1.201
89 1.172 1.188 1.178
90 1.151 1.163 1.155
91 1.141 1.150 1.144
92 1.131 1.137 1.133
93 1.120 1.125 1.122
94 1.109 1.112 1.110
95 1.097 1.098 1.097
96 1.083 1.084 1.084
97 1.069 1.069 1.069
98 1.054 1.054 1.054
99 1.040 1.040 1.040
100 1.000 1.000 1.000
<PAGE>
APPENDIX B -- ENHANCED
ENHANCED DEATH BENEFIT CORRIDOR
FACTORS FOR THE
GUIDELINE PREMIUM/CASH VALUE CORRIDOR TEST
FOR A LIFE INSURANCE POLICY
Attained Attained Attained Attained
Age Factor Age Factor Age Factor Age Factor
0 2.500 25 2.500 50 1.850 75 1.103
1 2.500 26 2.500 51 1.780 76 1.113
2 2.500 27 2.500 52 1.710 77 1.124
3 2.500 28 2.500 53 1.640 78 1.134
4 2.500 29 2.500 54 1.570 79 1.145
5 2.500 30 2.500 55 1.500 80 1.155
6 2.500 31 2.500 56 1.460 81 1.145
7 2.500 32 2.500 57 1.420 82 1.134
8 2.500 33 2.500 58 1.380 83 1.124
9 2.500 34 2.500 59 1.340 84 1.113
10 2.500 35 2.500 60 1.300 85 1.103
11 2.500 36 2.500 61 1.280 86 1.092
12 2.500 37 2.500 62 1.260 87 1.082
13 2.500 38 2.500 63 1.240 88 1.071
14 2.500 39 2.500 64 1.220 89 1.061
15 2.500 40 2.500 65 1.200 90 1.050
16 2.500 41 2.430 66 1.190 91 1.040
17 2.500 42 2.360 67 1.180 92 1.030
18 2.500 43 2.290 68 1.170 93 1.020
19 2.500 44 2.220 69 1.160 94 1.010
20 2.500 45 2.150 70 1.150 95 1.000
21 2.500 46 2.090 71 1.141 96 1.000
22 2.500 47 2.030 72 1.132 97 1.000
23 2.500 48 1.970 73 1.123 98 1.000
24 2.500 49 1.910 74 1.113 99 1.000
100 1.000
THE POLICY'S BASE DEATH BENEFIT AT ANY TIME WILL BE AT LEAST EQUAL TO
THE
ACCOUNT VALUE TIMES THE APPROPRIATE FACTOR FROM THIS TABLE.
